diff --git a/README.md b/README.md
index 893a19e..c997118 100644
--- a/README.md
+++ b/README.md
@@ -86,6 +86,7 @@ The report is versioned by `schema_version`; the models live in
 [`release_scope/_report.py`](https://github.com/modern-python/release-scope/blob/main/release_scope/_report.py).
 Top-level `jira` is `null` without a Jira token; otherwise it holds `issues` by key (summary, status, status category,
 issue type, linked GitLab changes), the `missing` keys Jira did not return, and an `error` if a Jira request failed.
+Warnings and errors, on services and in `jira`, are messages: a `code`, its `params`, and the English `text`.
 Each service lists its `candidates`: the tags a release could ship, newest first, each with its pipeline, the number of
 rows it ships, the in-scope Jira keys of those rows, and the compare link from production, or the tag's commit history
 when the service has no production deployment. One row, trimmed:
@@ -110,7 +111,8 @@ installed package and change only with it, so the page always matches the report
 
 Switches at the top pick the language, English or Russian, and the theme: as in the system, light, or dark. The page
 starts in the browser's language and remembers both choices in the browser. The copied lists and release post follow
-the language; warnings and errors from `collect`, and texts from GitLab and Jira, stay as written.
+the language, and so do warnings and errors from `collect`; texts from GitLab and Jira, such as titles, statuses and
+Jira's own error details, stay as written.
 
 **Services** lists every service with a production deployment or with rows, and every service that failed to collect,
 as one line: what production runs, the picked tag, how many merge requests or commits and Jira tasks it ships, failed jobs
@@ -150,7 +152,7 @@ release-report:
   rules:
     - if: $CI_PIPELINE_SOURCE == "schedule"
   script:
-    - uvx --from 'release-scope>=0.5,<0.6' release-scope collect --group team/backend --output public || [ $? -eq 1 ]
+    - uvx --from 'release-scope>=0.6,<0.7' release-scope collect --group team/backend --output public || [ $? -eq 1 ]
   pages: true
 ```
 
@@ -189,4 +191,4 @@ npx skills add modern-python/release-scope
 ```
 
 The agent reads the same environment variables as the CLI, so set them first as described under Configuration.
-The skill runs `release-scope>=0.5,<0.6`, the range whose flags and report schema it describes.
+The skill runs `release-scope>=0.6,<0.7`, the range whose flags and report schema it describes.
diff --git a/release_scope/__main__.py b/release_scope/__main__.py
index 9ef3611..fa8d669 100644
--- a/release_scope/__main__.py
+++ b/release_scope/__main__.py
@@ -97,11 +97,11 @@ def _collect_command(  # noqa: PLR0913, PLR0917
     write_site(output, report.model_dump_json(indent=2))
     if cache_path:
         cache.save(cache_path)
-    failed: typing.Final = [service for service in report.services if service.error]
+    failed: typing.Final = [service.error for service in report.services if service.error]
     rows: typing.Final = sum(len(service.rows) for service in report.services)
     typer.echo(f"{len(report.services)} services, {rows} rows, {len(failed)} failed -> {output}", err=True)
-    for service in failed:
-        typer.echo(f"Error: {service.error}", err=True)
+    for error in failed:
+        typer.echo(f"Error: {error.text}", err=True)
     jira_errors: typing.Final = _jira_errors(report)
     for message in jira_errors:
         typer.echo(f"Error: {message}", err=True)
@@ -129,7 +129,7 @@ def _jira_errors(report: Report) -> list[str]:
         return []
     errors: typing.Final = [f"Jira has no issue {key}." for key in report.jira_scope if key in report.jira.missing]
     if report.jira.error:
-        errors.append(report.jira.error)
+        errors.append(report.jira.error.text)
     return errors
 
 
diff --git a/release_scope/_errors.py b/release_scope/_errors.py
index d96ae7d..9590ce2 100644
--- a/release_scope/_errors.py
+++ b/release_scope/_errors.py
@@ -1,5 +1,7 @@
 import typing
 
+from release_scope._report import Message
+
 
 class ReleaseScopeError(Exception):
     exit_code: typing.ClassVar[int] = 1
@@ -24,4 +26,6 @@ def __init__(self, message: str, *, resource: str, status: int | None = None, re
 
 
 class JiraError(ReleaseScopeError):
-    pass
+    def __init__(self, message: Message) -> None:
+        super().__init__(message.text)
+        self.message = message
diff --git a/release_scope/_gitlab.py b/release_scope/_gitlab.py
index 65585d2..98028e3 100644
--- a/release_scope/_gitlab.py
+++ b/release_scope/_gitlab.py
@@ -1,5 +1,5 @@
 import dataclasses
-import datetime
+import datetime as dt
 import math
 import typing
 from urllib.parse import quote, unquote
@@ -54,7 +54,7 @@ class Commit(pydantic.BaseModel):
     title: str
     message: str = ""
     author_name: str | None = None
-    committed_date: datetime.datetime
+    committed_date: dt.datetime
     web_url: str | None = None
 
 
@@ -228,7 +228,7 @@ def list_first_parent_commits(
         )
 
     def list_merged_merge_requests(
-        self, project_id: int, *, target_branch: str, updated_after: datetime.datetime
+        self, project_id: int, *, target_branch: str, updated_after: dt.datetime
     ) -> list[MergeRequest]:
         merge_requests, _ = self._pages(
             f"{_API}/projects/{project_id}/merge_requests",
@@ -252,7 +252,7 @@ def commit_merge_requests(self, project_id: int, sha: str) -> list[MergeRequest]
         )
         return merge_requests
 
-    def list_push_pipelines(self, project_id: int, *, ref: str, updated_after: datetime.datetime) -> list[Pipeline]:
+    def list_push_pipelines(self, project_id: int, *, ref: str, updated_after: dt.datetime) -> list[Pipeline]:
         pipelines, _ = self._pages(
             f"{_API}/projects/{project_id}/pipelines",
             {"ref": ref, "source": "push", "updated_after": updated_after.isoformat()},
diff --git a/release_scope/_jira.py b/release_scope/_jira.py
index e33a14c..e4d717e 100644
--- a/release_scope/_jira.py
+++ b/release_scope/_jira.py
@@ -6,6 +6,7 @@
 import pydantic
 
 from release_scope._errors import JiraError
+from release_scope._messages import jira_status, jira_token_rejected, jira_unreachable
 
 
 _SEARCH: typing.Final = "/rest/api/2/search"
@@ -66,15 +67,12 @@ def _error_messages(exc: httpware.StatusError) -> str:
     return " ".join(str(message) for message in messages)
 
 
-def _translate(exc: httpware.ClientError, *, target: str) -> JiraError:
+def _translate(exc: httpware.ClientError, *, issue: str | None) -> JiraError:
     if isinstance(exc, httpware.UnauthorizedError):
-        return JiraError("Jira rejected the token (401). Check that it is valid and not expired.")
+        return JiraError(jira_token_rejected())
     if isinstance(exc, httpware.StatusError):
-        status: typing.Final = exc.response.status_code
-        details: typing.Final = _error_messages(exc)
-        suffix: typing.Final = f": {details.rstrip('.')}." if details else "."
-        return JiraError(f"Jira returned {status} for {target}{suffix}")
-    return JiraError(f"Jira request for {target} failed: {type(exc).__name__}.")
+        return JiraError(jira_status(exc.response.status_code, _error_messages(exc).rstrip("."), issue))
+    return JiraError(jira_unreachable(type(exc).__name__, issue))
 
 
 def _batches(keys: collections.abc.Sequence[str]) -> collections.abc.Iterator[collections.abc.Sequence[str]]:
@@ -106,7 +104,7 @@ def _search(self, jql: str) -> list[Issue]:
             try:
                 page = self.http.post(_SEARCH, json=body, response_model=_SearchResults)
             except httpware.ClientError as exc:
-                raise _translate(exc, target="the issue search") from exc
+                raise _translate(exc, issue=None) from exc
             issues.extend(page.issues)
             if not page.issues or len(issues) >= page.total:
                 return issues
@@ -115,4 +113,4 @@ def remote_links(self, key: str) -> list[RemoteLink]:
         try:
             return self.http.get(f"{_ISSUE}/{key}/remotelink", response_model=_RemoteLinks).root
         except httpware.ClientError as exc:
-            raise _translate(exc, target=f"the remote links of {key}") from exc
+            raise _translate(exc, issue=key) from exc
diff --git a/release_scope/_messages.py b/release_scope/_messages.py
index 449e12c..6e59be4 100644
--- a/release_scope/_messages.py
+++ b/release_scope/_messages.py
@@ -3,45 +3,136 @@
 
 from release_scope._errors import GitLabError
 from release_scope._gitlab import Project
+from release_scope._report import Message, MessageCode
 
 
 _RESOURCES: typing.Final[dict[str, tuple[str, tuple[str, ...]]]] = {
+    "project": ("the project", ()),
     "deployments": ("deployments", ("Environments", "CI/CD")),
     "pipelines": ("pipelines", ("CI/CD",)),
     "repository": ("the repository", ("Repository",)),
     "merge_requests": ("merge requests", ("Merge requests",)),
 }
 _PLURAL_FEATURES: typing.Final = frozenset({"Environments", "Merge requests"})
+_PERMISSIONS: typing.Final = "Visibility, project features, permissions"
 
 
-def _feature_setting(project: Project, feature: str) -> str:
-    return f"{project.web_url}/edit#js-shared-permissions → Visibility, project features, permissions → {feature}"
+def _settings_url(web_url: str) -> str:
+    return f"{web_url}/edit#js-shared-permissions"
 
 
-def explain_failure(project: Project, error: GitLabError) -> str:
-    name: typing.Final = project.path_with_namespace
-    resource, features = _RESOURCES.get(error.resource, ("project data", ()))
+def explain_failure(name: str, web_url: str, error: GitLabError) -> Message:
+    label, features = _RESOURCES.get(error.resource, ("project data", ()))
     if error.status is None:
-        return f"{name}: GitLab request for {resource} failed ({error.reason})."
+        return Message(
+            code=MessageCode.GITLAB_UNREACHABLE,
+            params={"project": name, "resource": error.resource, "reason": error.reason},
+            text=f"{name}: GitLab request for {label} failed ({error.reason}).",
+        )
     if error.status != http.HTTPStatus.FORBIDDEN:
-        return f"{name}: GitLab returned {error.status} for {resource}."
+        return Message(
+            code=MessageCode.GITLAB_STATUS,
+            params={"project": name, "resource": error.resource, "status": error.status},
+            text=f"{name}: GitLab returned {error.status} for {label}.",
+        )
+    settings: typing.Final = _settings_url(web_url)
+    members: typing.Final = f"{web_url}/-/project_members"
     checks: typing.Final = [
-        f"- {feature} {'are' if feature in _PLURAL_FEATURES else 'is'} enabled: {_feature_setting(project, feature)}"
+        f"- {feature} {'are' if feature in _PLURAL_FEATURES else 'is'} enabled: {settings} → {_PERMISSIONS} → {feature}"
         for feature in features
     ]
-    checks.append(f"- the token's user has a role that can read them: {project.web_url}/-/project_members")
-    return "\n".join([f"{name}: GitLab denied access to {resource} (403). Check that:", *checks])
+    checks.append(f"- the token's user has a role that can read them: {members}")
+    return Message(
+        code=MessageCode.GITLAB_DENIED,
+        params={
+            "project": name,
+            "resource": error.resource,
+            "features": list(features),
+            "settings_url": settings,
+            "members_url": members,
+        },
+        text="\n".join([f"{name}: GitLab denied access to {label} (403). Check that:", *checks]),
+    )
 
 
-def skip_reason(project: Project) -> str | None:
+def skip_reason(project: Project) -> Message | None:
+    settings: typing.Final = _settings_url(project.web_url)
     if project.builds_access_level == "disabled":
-        return (
-            "CI/CD is disabled, so it has no pipelines or deployments. "
-            f"Enable it at {_feature_setting(project, 'CI/CD')}."
+        return Message(
+            code=MessageCode.CI_DISABLED,
+            params={"settings_url": settings},
+            text="CI/CD is disabled, so it has no pipelines or deployments. "
+            f"Enable it at {settings} → {_PERMISSIONS} → CI/CD.",
         )
     if project.environments_access_level == "disabled":
-        return (
-            "Environments are disabled, so it has no deployments. "
-            f"Enable them at {_feature_setting(project, 'Environments')}."
+        return Message(
+            code=MessageCode.ENVIRONMENTS_DISABLED,
+            params={"settings_url": settings},
+            text="Environments are disabled, so it has no deployments. "
+            f"Enable them at {settings} → {_PERMISSIONS} → Environments.",
         )
     return None
+
+
+def no_default_branch() -> Message:
+    return Message(code=MessageCode.NO_DEFAULT_BRANCH, text="Project has no default branch.")
+
+
+def no_production(environment: str, branch: str) -> Message:
+    return Message(
+        code=MessageCode.NO_PRODUCTION,
+        params={"environment": environment, "branch": branch},
+        text=f"No successful deployment to '{environment}'; rows run from the first commit of {branch}.",
+    )
+
+
+def commits_truncated(max_commits: int) -> Message:
+    return Message(
+        code=MessageCode.COMMITS_TRUNCATED,
+        params={"max_commits": max_commits},
+        text=f"Stopped after {max_commits} commits; older changes are omitted.",
+    )
+
+
+def tags_truncated() -> Message:
+    return Message(code=MessageCode.TAGS_TRUNCATED, text="Tag list was truncated; some tags may be missing from rows.")
+
+
+def merged_elsewhere(iid: int, target_branch: str, default_branch: str) -> Message:
+    return Message(
+        code=MessageCode.MERGED_ELSEWHERE,
+        params={"iid": iid, "target_branch": target_branch, "default_branch": default_branch},
+        text=f"!{iid} was merged into {target_branch}, not {default_branch}.",
+    )
+
+
+def _jira_target(issue: str | None) -> tuple[dict[str, str], str]:
+    if issue is None:
+        return {}, "the issue search"
+    return {"issue": issue}, f"the remote links of {issue}"
+
+
+def jira_token_rejected() -> Message:
+    return Message(
+        code=MessageCode.JIRA_TOKEN_REJECTED,
+        text="Jira rejected the token (401). Check that it is valid and not expired.",
+    )
+
+
+def jira_status(status: int, detail: str, issue: str | None) -> Message:
+    params, target = _jira_target(issue)
+    suffix: typing.Final = f": {detail}." if detail else "."
+    return Message(
+        code=MessageCode.JIRA_STATUS,
+        params={"status": status, "detail": detail, **params},
+        text=f"Jira returned {status} for {target}{suffix}",
+    )
+
+
+def jira_unreachable(reason: str, issue: str | None) -> Message:
+    params, target = _jira_target(issue)
+    return Message(
+        code=MessageCode.JIRA_UNREACHABLE,
+        params={"reason": reason, **params},
+        text=f"Jira request for {target} failed: {reason}.",
+    )
diff --git a/release_scope/_report.py b/release_scope/_report.py
index 60fdbaf..74f7e2f 100644
--- a/release_scope/_report.py
+++ b/release_scope/_report.py
@@ -1,10 +1,33 @@
-import datetime
+import datetime as dt
+import enum
 import typing
 
 import pydantic
 
 
-SCHEMA_VERSION: typing.Final = 3
+SCHEMA_VERSION: typing.Final = 4
+
+
+class MessageCode(enum.StrEnum):
+    CI_DISABLED = "ci_disabled"
+    ENVIRONMENTS_DISABLED = "environments_disabled"
+    NO_DEFAULT_BRANCH = "no_default_branch"
+    NO_PRODUCTION = "no_production"
+    COMMITS_TRUNCATED = "commits_truncated"
+    TAGS_TRUNCATED = "tags_truncated"
+    MERGED_ELSEWHERE = "merged_elsewhere"
+    GITLAB_UNREACHABLE = "gitlab_unreachable"
+    GITLAB_STATUS = "gitlab_status"
+    GITLAB_DENIED = "gitlab_denied"
+    JIRA_TOKEN_REJECTED = "jira_token_rejected"
+    JIRA_STATUS = "jira_status"
+    JIRA_UNREACHABLE = "jira_unreachable"
+
+
+class Message(pydantic.BaseModel):
+    code: MessageCode
+    params: dict[str, str | int | list[str]] = pydantic.Field(default_factory=dict)
+    text: str
 
 
 class FailedJob(pydantic.BaseModel):
@@ -45,7 +68,7 @@ class CommitRef(pydantic.BaseModel):
     title: str
     url: str | None
     author: str | None
-    committed_at: datetime.datetime
+    committed_at: dt.datetime
 
 
 class JiraKeyRef(pydantic.BaseModel):
@@ -95,8 +118,8 @@ class Service(pydantic.BaseModel):
     rows: list[Row] = pydantic.Field(default_factory=list)
     candidates: list[Candidate] = pydantic.Field(default_factory=list)
     truncated: bool = False
-    warnings: list[str] = pydantic.Field(default_factory=list)
-    error: str | None = None
+    warnings: list[Message] = pydantic.Field(default_factory=list)
+    error: Message | None = None
     release: Release | None = None
 
 
@@ -122,12 +145,12 @@ class JiraIssue(pydantic.BaseModel):
 class JiraState(pydantic.BaseModel):
     issues: dict[str, JiraIssue] = pydantic.Field(default_factory=dict)
     missing: list[str] = pydantic.Field(default_factory=list)
-    error: str | None = None
+    error: Message | None = None
 
 
 class Report(pydantic.BaseModel):
-    schema_version: typing.Literal[3] = SCHEMA_VERSION
-    collected_at: datetime.datetime
+    schema_version: typing.Literal[4] = SCHEMA_VERSION
+    collected_at: dt.datetime
     production_environment: str
     services: list[Service]
     jira: JiraState | None = None
diff --git a/release_scope/_static/index.html b/release_scope/_static/index.html
index 380a5ee..402b73a 100644
--- a/release_scope/_static/index.html
+++ b/release_scope/_static/index.html
@@ -55,6 +55,7 @@
   .muted { color: var(--muted); }
   .bad { color: var(--bad); }
   .warn { color: var(--warn); }
+  .message { white-space: pre-line; }
   .scroll { overflow-x: auto; }
   .outputs { display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 12px; margin-top: 16px; }
   .outputs .wide { grid-column: 1 / -1; }
@@ -114,8 +115,8 @@ <h1 x-text="report.jira_scope.length ? t('titleIssues', { keys: report.jira_scop
           </li>
         </template>
       </ul>
-      <template x-for="message in problems" :key="message">
-        <p class="bad" x-text="message"></p>
+      <template x-for="item in problems" :key="item.text">
+        <p class="bad message" x-text="message(item)"></p>
       </template>
 
       <h2 x-text="t('services')"></h2>
@@ -142,9 +143,9 @@ <h2 x-text="t('services')"></h2>
                 <span> · <span x-text="item.name"></span> <a :href="item.deployment_url" x-text="item.ref"></a></span>
               </template>
             </p>
-            <p x-show="service.error" class="bad" x-text="service.error"></p>
-            <template x-for="warning in service.warnings" :key="warning">
-              <p class="warn" x-text="warning"></p>
+            <p x-show="service.error" class="bad message" x-text="service.error && message(service.error)"></p>
+            <template x-for="warning in service.warnings" :key="warning.text">
+              <p class="warn message" x-text="message(warning)"></p>
             </template>
             <p x-show="service.release && service.release.pending_merge_requests.length">
               <span x-text="t('notMerged')"></span>
@@ -326,6 +327,7 @@ <h3 x-text="t('releasePost')"></h3>
       noTagYet: "no tag yet",
       upToDate: "up to date",
       rows: { one: "{count} merge request or commit", other: "{count} merge requests or commits" },
+      rowsOf: { one: "{count} merge request or commit", other: "{count} merge requests or commits" },
       taskCount: { one: "{count} task", other: "{count} tasks" },
       shipsOf: "{shipped} of {rows}",
       failedCount: "❌ {count} failed",
@@ -372,27 +374,28 @@ <h3 x-text="t('releasePost')"></h3>
       loadFailed: "Не удалось загрузить отчёт: {error}.",
       title: "Состав релиза",
       titleIssues: "Состав релиза: {keys}",
-      rangeStart: "Собрано {at} UTC. Изменения считаются от коммита на",
-      rangeEnd: "до головы основной ветки.",
+      rangeStart: "Данные собраны {at} UTC. Показаны изменения от коммита на",
+      rangeEnd: "до последнего коммита основной ветки.",
       rangeEndIssues:
-        "до головы основной ветки; строки выше последнего MR или коммита, связанного с задачами, вне скоупа.",
+        "до последнего коммита основной ветки; строки выше последнего MR или коммита, связанного с задачами, вне скоупа.",
       notInJira: "нет в Jira",
       services: "Сервисы",
       servicesIntro:
-        "Откройте сервис и выберите тег для релиза: в него войдут все MR и коммиты от его строки до прода. Выбор хранится в адресе страницы, так что им можно поделиться ссылкой.",
-      ignored: "Из адреса пропущены теги, которых нет в этом отчёте: {picks}.",
+        "Откройте сервис и выберите тег для релиза: в релиз войдут все MR и коммиты от строки этого тега до прода. Выбор хранится в адресе страницы, так что им можно поделиться ссылкой.",
+      ignored: "В адресе есть выбор, которого нет в этом отчёте; он не учтён: {picks}.",
       failedToCollect: "не удалось собрать",
       notInProduction: "нет на проде",
       pickTag: "выберите тег",
       noTagYet: "тега ещё нет",
       upToDate: "всё на проде",
       rows: { one: "{count} MR или коммит", few: "{count} MR или коммита", many: "{count} MR или коммитов" },
+      rowsOf: { one: "{count} MR или коммита", few: "{count} MR или коммитов", many: "{count} MR или коммитов" },
       taskCount: { one: "{count} задача", few: "{count} задачи", many: "{count} задач" },
       shipsOf: "{shipped} из {rows}",
       failedCount: "❌ упало: {count}",
       allowedCount: "упало, но падать разрешено: {count}",
       rangeCut: "диапазон обрезан",
-      rangeCutTitle: "Старые MR и коммиты не собраны; подробности внутри",
+      rangeCutTitle: "Более ранние MR и коммиты не собраны; подробности внутри",
       notMerged: "Не влиты:",
       columnTag: "Тег",
       columnChange: "Изменение",
@@ -406,7 +409,7 @@ <h3 x-text="t('releasePost')"></h3>
       allowedToFail: "(падать разрешено)",
       clearPick: "Сбросить выбор",
       release: "Релиз",
-      noCandidates: "Ни у одного сервиса нет тега между продом и головой основной ветки.",
+      noCandidates: "Ни у одного сервиса нет тега между продом и последним коммитом основной ветки.",
       pickToFill: "Выберите тег в сервисе выше, чтобы заполнить списки.",
       copyFailed: "Кнопка копирования работает только по HTTPS; выделите текст в поле.",
       tasks: "Задачи Jira ({count})",
@@ -422,7 +425,51 @@ <h3 x-text="t('releasePost')"></h3>
       postTasks: "**Задачи Jira ({count})**",
       postNone: "- нет",
       postPipeline: "пайплайн #{id}",
-      legend: "Обозначения: ✅ успешно · ❌ упал · 🔄 выполняется · ⏭ отменён или пропущен · ⚠️ нет пайплайна",
+      legend: "Обозначения: ✅ прошёл · ❌ упал · 🔄 выполняется · ⏭ отменён или пропущен · ⚠️ нет пайплайна",
+    },
+  };
+
+  const PERMISSIONS = "Visibility, project features, permissions";
+  const RESOURCES_DATIVE_RU = {
+    project: "проекту",
+    deployments: "деплоям",
+    pipelines: "пайплайнам",
+    repository: "репозиторию",
+    merge_requests: "MR",
+  };
+  const RESOURCES_ACCUSATIVE_RU = {
+    project: "проект",
+    deployments: "деплои",
+    pipelines: "пайплайны",
+    repository: "репозиторий",
+    merge_requests: "MR",
+  };
+  const resourceDativeRu = (p) => RESOURCES_DATIVE_RU[p.resource] ?? "данным проекта";
+  const resourceAccusativeRu = (p) => RESOURCES_ACCUSATIVE_RU[p.resource] ?? "данные проекта";
+  const jiraTargetRu = (p) => (p.issue ? `при чтении внешних ссылок задачи ${p.issue}` : "при поиске задач");
+  const MESSAGES = {
+    ru: {
+      ci_disabled: (p) =>
+        `В проекте отключён CI/CD, поэтому у него нет пайплайнов и деплоев. Включите CI/CD: ${p.settings_url} → ${PERMISSIONS} → CI/CD.`,
+      environments_disabled: (p) =>
+        `В проекте отключены Environments, поэтому у него нет деплоев. Включите их: ${p.settings_url} → ${PERMISSIONS} → Environments.`,
+      no_default_branch: () => "У проекта нет основной ветки.",
+      no_production: (p) =>
+        `Нет успешного деплоя на «${p.environment}»; строки начинаются с первого коммита ветки ${p.branch}.`,
+      commits_truncated: (p) => `Достигнут лимит коммитов (${p.max_commits}); более старые изменения не показаны.`,
+      tags_truncated: () => "Список тегов обрезан; у некоторых строк теги могут не отображаться.",
+      merged_elsewhere: (p) => `!${p.iid} влит в ${p.target_branch}, а не в ${p.default_branch}.`,
+      gitlab_unreachable: (p) => `${p.project}: не удалось получить ${resourceAccusativeRu(p)} из GitLab (${p.reason}).`,
+      gitlab_status: (p) => `${p.project}: не удалось получить ${resourceAccusativeRu(p)} из GitLab: ответ ${p.status}.`,
+      gitlab_denied: (p) =>
+        [
+          `${p.project}: GitLab отказал в доступе к ${resourceDativeRu(p)} (403). Проверьте, что:`,
+          ...p.features.map((feature) => `- включено «${feature}»: ${p.settings_url} → ${PERMISSIONS} → ${feature}`),
+          `- у владельца токена есть роль с доступом к ${resourceDativeRu(p)}: ${p.members_url}`,
+        ].join("\n"),
+      jira_token_rejected: () => "Jira отклонила токен (401). Проверьте, что он действителен и не истёк.",
+      jira_status: (p) => `Jira вернула ${p.status} ${jiraTargetRu(p)}${p.detail ? `: ${p.detail}.` : "."}`,
+      jira_unreachable: (p) => `Не удалось обратиться к Jira ${jiraTargetRu(p)}: ${p.reason}.`,
     },
   };
 
@@ -479,6 +526,10 @@ <h3 x-text="t('releasePost')"></h3>
         }
         return text.replace(/\{(\w+)\}/g, (match, name) => (name in params ? params[name] : match));
       },
+      message(item) {
+        const render = MESSAGES[this.lang] && MESSAGES[this.lang][item.code];
+        return render ? render(item.params) : item.text;
+      },
       setLang(lang) {
         this.lang = lang;
         document.documentElement.lang = lang;
@@ -605,7 +656,8 @@ <h3 x-text="t('releasePost')"></h3>
         const candidate = this.pickOf(service);
         const rows = this.t("rows", { count: service.rows.length });
         if (candidate) {
-          const shipped = this.t("shipsOf", { shipped: candidate.rows, rows });
+          const of = this.t("rowsOf", { count: service.rows.length });
+          const shipped = this.t("shipsOf", { shipped: candidate.rows, rows: of });
           return `${shipped} · ${this.t("taskCount", { count: candidate.jira_keys.length })}`;
         }
         if (!service.rows.length) return "";
diff --git a/release_scope/_use_case.py b/release_scope/_use_case.py
index e32e80b..e9a7ea6 100644
--- a/release_scope/_use_case.py
+++ b/release_scope/_use_case.py
@@ -1,6 +1,6 @@
 import collections.abc
 import dataclasses
-import datetime
+import datetime as dt
 import http
 import typing
 from urllib.parse import quote
@@ -12,7 +12,15 @@
 from release_scope._jira import JiraApi
 from release_scope._jira_keys import extract_jira_keys
 from release_scope._links import parse_gitlab_link
-from release_scope._messages import explain_failure, skip_reason
+from release_scope._messages import (
+    commits_truncated,
+    explain_failure,
+    merged_elsewhere,
+    no_default_branch,
+    no_production,
+    skip_reason,
+    tags_truncated,
+)
 from release_scope._report import (
     CommitRef,
     EnvironmentState,
@@ -22,6 +30,7 @@
     JiraState,
     LinkedChange,
     MergeRequestRef,
+    Message,
     PipelineState,
     Release,
     Report,
@@ -95,7 +104,7 @@ class _LinkTarget:
     merged: set[int]
     shas: list[str]
     pending: list[MergeRequestRef]
-    warnings: list[str]
+    warnings: list[Message]
 
     def matches(self, draft: RowDraft) -> bool:
         return any(item.iid in self.merged for item in draft.merge_requests) or any(
@@ -122,7 +131,7 @@ def __call__(
             for project in self._resolve_projects(groups=groups, projects=projects, include_subgroups=include_subgroups)
         ]
         return Report(
-            collected_at=datetime.datetime.now(datetime.UTC),
+            collected_at=dt.datetime.now(dt.UTC),
             production_environment=self.settings.production_environment,
             services=services,
             jira=self._read_issues(self.jira, _row_keys(services)) if self.jira else None,
@@ -148,7 +157,7 @@ def for_issues(self, *, keys: collections.abc.Sequence[str], cache: Cache) -> Re
             state.missing.extend(row_state.missing)
             state.error = row_state.error
         return Report(
-            collected_at=datetime.datetime.now(datetime.UTC),
+            collected_at=dt.datetime.now(dt.UTC),
             production_environment=self.settings.production_environment,
             services=services,
             jira=state,
@@ -159,7 +168,8 @@ def _scoped_service(self, path: str, links: list[LinkedChange], cache: Cache) ->
         try:
             project: typing.Final = self.api.get_project(path)
         except GitLabError as exc:
-            return Service(project=path, project_url=links[0].project_url, error=f"{path}: {exc}")
+            project_url: typing.Final = links[0].project_url
+            return Service(project=path, project_url=project_url, error=explain_failure(path, project_url, exc))
         return self._collect_or_explain(project, cache, links=links)
 
     def _collect_or_explain(self, project: Project, cache: Cache, *, links: list[LinkedChange] | None) -> Service:
@@ -168,7 +178,9 @@ def _collect_or_explain(self, project: Project, cache: Cache, *, links: list[Lin
         except GitLabError as exc:
             cache.keep_project(project.id)
             return Service(
-                project=project.path_with_namespace, project_url=project.web_url, error=explain_failure(project, exc)
+                project=project.path_with_namespace,
+                project_url=project.web_url,
+                error=explain_failure(project.path_with_namespace, project.web_url, exc),
             )
 
     def _read_issues(self, jira: JiraApi, keys: collections.abc.Sequence[str]) -> JiraState:
@@ -178,7 +190,7 @@ def _read_issues(self, jira: JiraApi, keys: collections.abc.Sequence[str]) -> Ji
         try:
             issues: typing.Final = {issue.key: issue for issue in jira.search_issues(keys)}
         except JiraError as exc:
-            state.error = str(exc)
+            state.error = exc.message
             return state
         for key in keys:
             issue = issues.get(key)
@@ -198,7 +210,7 @@ def _read_issues(self, jira: JiraApi, keys: collections.abc.Sequence[str]) -> Ji
             for key, issue in state.issues.items():
                 issue.links = self._linked_changes(jira, key)
         except JiraError as exc:
-            state.error = str(exc)
+            state.error = exc.message
         return state
 
     def _linked_changes(self, jira: JiraApi, key: str) -> list[LinkedChange]:
@@ -248,13 +260,10 @@ def _collect_service(self, project: Project, cache: Cache, *, links: list[Linked
             (item for item in service.environments if item.name == self.settings.production_environment), None
         )
         if project.default_branch is None:
-            service.warnings.append("Project has no default branch.")
+            service.warnings.append(no_default_branch())
             return service
         if production is None:
-            service.warnings.append(
-                f"No successful deployment to '{self.settings.production_environment}'; "
-                f"rows run from the first commit of {project.default_branch}."
-            )
+            service.warnings.append(no_production(self.settings.production_environment, project.default_branch))
 
         walk: typing.Final = self._walk(
             project, project.default_branch, production.sha if production else None, service, cache
@@ -287,14 +296,14 @@ def _walk(
         walk: typing.Final = _Walk(truncated=truncated)
         service.truncated = truncated
         if truncated:
-            service.warnings.append(f"Stopped after {self.settings.max_commits} commits; older changes are omitted.")
+            service.warnings.append(commits_truncated(self.settings.max_commits))
         if not commits:
             return walk
         since: typing.Final = min(commit.committed_date for commit in commits)
         walk.drafts = group_rows(commits, self._commit_merge_requests(project, default_branch, commits, since, cache))
-        tags, tags_truncated = self.api.list_tags(project.id)
-        if tags_truncated:
-            service.warnings.append("Tag list was truncated; some tags may be missing from rows.")
+        tags, tag_list_cut = self.api.list_tags(project.id)
+        if tag_list_cut:
+            service.warnings.append(tags_truncated())
         for tag in tags:
             walk.tags_by_sha.setdefault(tag.commit.id, []).append(tag.name)
         walk.main_pipelines = self._latest_by_sha(
@@ -330,7 +339,7 @@ def _link_target(
     ) -> _LinkTarget:
         merged: typing.Final[set[int]] = set()
         pending: typing.Final[list[MergeRequestRef]] = []
-        warnings: typing.Final[list[str]] = []
+        warnings: typing.Final[list[Message]] = []
         for link in links:
             if link.iid is None:
                 continue
@@ -338,9 +347,7 @@ def _link_target(
             if merge_request.state != "merged":
                 pending.append(_merge_request_ref(merge_request))
             elif merge_request.target_branch != default_branch:
-                warnings.append(
-                    f"!{merge_request.iid} was merged into {merge_request.target_branch}, not {default_branch}."
-                )
+                warnings.append(merged_elsewhere(merge_request.iid, merge_request.target_branch, default_branch))
             else:
                 merged.add(merge_request.iid)
         return _LinkTarget(
@@ -380,7 +387,7 @@ def _release(self, project: Project, target: _LinkTarget, walk: _Walk, index: in
         )
 
     def _commit_merge_requests(
-        self, project: Project, default_branch: str, commits: list[Commit], since: datetime.datetime, cache: Cache
+        self, project: Project, default_branch: str, commits: list[Commit], since: dt.datetime, cache: Cache
     ) -> dict[str, list[MergeRequest]]:
         merged: typing.Final = self.api.list_merged_merge_requests(
             project.id, target_branch=default_branch, updated_after=since
diff --git a/skills/release-scope/SKILL.md b/skills/release-scope/SKILL.md
index 4a64f14..501225b 100644
--- a/skills/release-scope/SKILL.md
+++ b/skills/release-scope/SKILL.md
@@ -14,7 +14,7 @@ description: >
 through uvx with this version range; it matches the flags and report schema described here:
 
 ```bash
-uvx --from 'release-scope>=0.5,<0.6' release-scope --help
+uvx --from 'release-scope>=0.6,<0.7' release-scope --help
 ```
 
 ## Check the settings
@@ -56,7 +56,7 @@ run and only saves requests:
 ```bash
 out="${XDG_CACHE_HOME:-$HOME/.cache}/release-scope"
 mkdir -p "$out"
-uvx --from 'release-scope>=0.5,<0.6' release-scope collect --project team/backend/shop \
+uvx --from 'release-scope>=0.6,<0.7' release-scope collect --project team/backend/shop \
   --output "$out/site" --cache "$out/cache.json"
 ```
 
@@ -76,12 +76,13 @@ For `2` to `4` nothing was written; show the message and stop.
 Read `$out/site/report.json` and answer the user's question from it, briefly.
 
 - `services[]`: `project`, `environments` (what each environment runs), `rows` (newest first, from the default
-  branch head down to production), `warnings`, `error`.
+  branch head down to production), `warnings`, `error`. Warnings and errors are messages: read their `text`;
+  `code` and `params` carry the same facts in structured form.
 - A row is one merged merge request or a direct commit: `merge_requests`, `commits`, `tags` pointing into it,
   `environments` already running it, `jira_keys`, and `main_pipeline` with `failed_jobs`. Tag pipelines carry their
   own `failed_jobs`.
 - A service with no rows is up to date with production.
-- A service never deployed to production has a warning saying so; its rows run down to the first commit of the
+- A service never deployed to production has a `no_production` warning; its rows run down to the first commit of the
   default branch and its `compare_url` lists the tag's commits.
 - `truncated: true`: the walk stopped at `RELEASE_SCOPE_MAX_COMMITS`, so the oldest candidates miss rows and keys.
 - `candidates` (newest first): the tags a release could ship, each with `tag` and its `pipeline`, `rows` (how many
@@ -89,7 +90,7 @@ Read `$out/site/report.json` and answer the user's question from it, briefly.
   `compare_url`.
   To answer which issues a set of tags releases, merge the `jira_keys` of the picked candidates.
 - `jira.issues` by key: `summary`, `status`, `status_category` (anything but `done` is not done), `links` to GitLab
-  merge requests and commits. `jira.missing` lists keys Jira did not return; `jira.error` a failed request. `jira` is
+  merge requests and commits. `jira.missing` lists keys Jira did not return; `jira.error` a failed request, as a message. `jira` is
   `null` without a Jira token.
 - In a `--jira` report, `jira_scope` lists the issues, rows with `linked: true` are the ones the issues point to,
   rows with `in_scope: false` sit above the latest linked change and do not ship with the issues, and each service
diff --git a/tests/test_cli.py b/tests/test_cli.py
index 4ad43a4..c918aa3 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -49,7 +49,7 @@ def test_collect_writes_report_and_cache(gitlab: respx.Router, tmp_path: pathlib
         "report.json",
     ]
     report: typing.Final = json.loads((output / "report.json").read_text())
-    assert report["schema_version"] == 3
+    assert report["schema_version"] == 4
     assert report["jira"] is None
     assert report["production_environment"] == "production"
     assert [len(item["rows"]) for item in report["services"]] == [5]
@@ -153,7 +153,7 @@ def test_collect_for_jira_issues_writes_a_scoped_report(tmp_path: pathlib.Path)
     assert report["jira_scope"] == ["SHOP-12"]
     assert [item["project"] for item in report["services"]] == ["team/svc", "team/web", "team/worker"]
     assert json.loads(cache.read_text())["merge_requests"]["1"]["12"]["iid"] == 12
-    assert "Error: team/web: GitLab returned 404" in result.output
+    assert "Error: team/web: GitLab returned 404 for the project." in result.output
 
 
 @pytest.mark.usefixtures("cli_env", "jira_env", "scoped")
diff --git a/tests/test_page.py b/tests/test_page.py
new file mode 100644
index 0000000..7c5238d
--- /dev/null
+++ b/tests/test_page.py
@@ -0,0 +1,32 @@
+import importlib.resources
+import re
+import typing
+
+from release_scope._report import MessageCode
+
+
+_PAGE: typing.Final = importlib.resources.files("release_scope").joinpath("_static/index.html").read_text()
+
+
+def _block(start: str, end: str) -> str:
+    return _PAGE[_PAGE.index(start) : _PAGE.index(end)]
+
+
+def _keys(block: str, indent: int) -> set[str]:
+    return set(re.findall(rf"^ {{{indent}}}(\w+):", block, re.MULTILINE))
+
+
+def test_every_translation_key_exists_in_both_languages() -> None:
+    strings: typing.Final = _block("const STRINGS = {", "const PERMISSIONS")
+    english, russian = strings.split("\n    ru: {")
+    used: typing.Final = set(re.findall(r"(?<!\w)t\([\"'](\w+)[\"']", _PAGE))
+
+    assert used
+    assert used <= _keys(english, 6)
+    assert _keys(english, 6) == _keys(russian, 6)
+
+
+def test_every_message_code_has_a_russian_rendering() -> None:
+    russian: typing.Final = _block("const MESSAGES = {", "const PLURALS")
+
+    assert _keys(russian, 6) == {code.value for code in MessageCode}
diff --git a/tests/test_scope.py b/tests/test_scope.py
index 51dde78..d0c5491 100644
--- a/tests/test_scope.py
+++ b/tests/test_scope.py
@@ -8,7 +8,7 @@
 from release_scope._cache import Cache
 from release_scope._gitlab import GitLabApi
 from release_scope._jira import JiraApi
-from release_scope._report import Report, Service
+from release_scope._report import Message, MessageCode, Report, Service
 from release_scope._settings import GitLabConfig, Settings
 from release_scope._use_case import CollectUseCase
 from tests.payloads import (
@@ -52,9 +52,13 @@ def test_scope_collects_every_service_the_issues_link_to() -> None:
 
     assert report.jira_scope == ["SHOP-12"]
     assert [item.project for item in report.services] == ["team/svc", "team/web", "team/worker"]
-    assert _service(report, "team/web").error == "team/web: GitLab returned 404 for /api/v4/projects/team/web."
+    assert _service(report, "team/web").error == Message(
+        code=MessageCode.GITLAB_STATUS,
+        params={"project": "team/web", "resource": "project", "status": 404},
+        text="team/web: GitLab returned 404 for the project.",
+    )
     assert _service(report, "team/web").project_url == f"{ENDPOINT}/team/web"
-    assert _service(report, "team/worker").warnings[0].startswith("CI/CD is disabled")
+    assert _service(report, "team/worker").warnings[0].code == MessageCode.CI_DISABLED
 
 
 @pytest.mark.httpx2(assert_all_called=False)
@@ -139,7 +143,13 @@ def test_open_and_off_branch_merge_requests_are_reported(scoped: respx.Router) -
     assert service.release is not None
     assert service.release.state == "not_merged"
     assert [item.iid for item in service.release.pending_merge_requests] == [13]
-    assert service.warnings == ["!14 was merged into release/1.x, not main."]
+    assert service.warnings == [
+        Message(
+            code=MessageCode.MERGED_ELSEWHERE,
+            params={"iid": 14, "target_branch": "release/1.x", "default_branch": "main"},
+            text="!14 was merged into release/1.x, not main.",
+        )
+    ]
 
 
 @pytest.mark.httpx2(assert_all_called=False)
@@ -198,6 +208,7 @@ def test_scope_stops_when_jira_fails(scoped: respx.Router) -> None:
     assert report.services == []
     assert report.jira is not None
     assert report.jira.error is not None
+    assert report.jira.error.code == MessageCode.JIRA_TOKEN_REJECTED
 
 
 @pytest.mark.httpx2(assert_all_called=False)
@@ -216,4 +227,6 @@ def test_a_failing_scoped_service_keeps_the_others(scoped: respx.Router) -> None
 
     report: typing.Final = _scope()
 
-    assert _service(report).error == "team/svc: GitLab returned 500 for merge requests."
+    error: typing.Final = _service(report).error
+    assert error is not None
+    assert error.text == "team/svc: GitLab returned 500 for merge requests."
diff --git a/tests/test_use_case.py b/tests/test_use_case.py
index ac54f1b..467e1f3 100644
--- a/tests/test_use_case.py
+++ b/tests/test_use_case.py
@@ -12,7 +12,7 @@
 from release_scope._errors import AuthError, GitLabError
 from release_scope._gitlab import GitLabApi
 from release_scope._jira import JiraApi
-from release_scope._report import Report, Service
+from release_scope._report import Message, MessageCode, Report, Service
 from release_scope._settings import GitLabConfig, Settings
 from release_scope._use_case import CollectUseCase
 from tests.payloads import (
@@ -266,7 +266,8 @@ def test_jira_failure_is_reported_and_services_are_kept(
     report: typing.Final = _collect(with_jira=True)
 
     assert report.jira is not None
-    assert report.jira.error == error
+    assert report.jira.error is not None
+    assert report.jira.error.text == error
     assert report.jira.issues == {}
     assert len(_only_service(report).rows) == 5
 
@@ -293,7 +294,11 @@ def test_remote_link_failure_is_reported_and_keeps_the_issues(jira: respx.Router
     state: typing.Final = _collect(with_jira=True).jira
 
     assert state is not None
-    assert state.error == "Jira returned 404 for the remote links of SHOP-12."
+    assert state.error == Message(
+        code=MessageCode.JIRA_STATUS,
+        params={"status": 404, "detail": "", "issue": "SHOP-12"},
+        text="Jira returned 404 for the remote links of SHOP-12.",
+    )
     assert sorted(state.issues) == ["SHOP-12", "SHOP-9"]
 
 
@@ -337,7 +342,7 @@ def test_a_failing_service_keeps_its_cache_and_does_not_stop_the_others(gitlab:
 
     report: typing.Final = _collect(next_cache)
 
-    assert [(item.project, item.error) for item in report.services] == [
+    assert [(item.project, item.error and item.error.text) for item in report.services] == [
         ("team/broken", "team/broken: GitLab returned 500 for deployments."),
         ("team/svc", "team/svc: GitLab returned 502 for deployments."),
     ]
@@ -352,7 +357,19 @@ def test_forbidden_deployments_fail_only_that_service_and_say_where_to_look(gitl
     report: typing.Final = _collect()
 
     assert [item.project for item in report.services] == ["team/nodeploy", "team/svc"]
-    assert report.services[0].error == (
+    error: typing.Final = report.services[0].error
+    assert error is not None
+    assert (error.code, error.params) == (
+        MessageCode.GITLAB_DENIED,
+        {
+            "project": "team/nodeploy",
+            "resource": "deployments",
+            "features": ["Environments", "CI/CD"],
+            "settings_url": settings,
+            "members_url": f"{ENDPOINT}/team/nodeploy/-/project_members",
+        },
+    )
+    assert error.text == (
         "team/nodeploy: GitLab denied access to deployments (403). Check that:\n"
         f"- Environments are enabled: {settings} → Visibility, project features, permissions → Environments\n"
         f"- CI/CD is enabled: {settings} → Visibility, project features, permissions → CI/CD\n"
@@ -378,7 +395,8 @@ def test_forbidden_resource_lists_the_feature_that_guards_it(
 
     error: typing.Final = _only_service(_collect()).error
 
-    assert error == (
+    assert error is not None
+    assert error.text == (
         f"team/svc: GitLab denied access to {resource} (403). Check that:\n"
         f"- {enabled}: {settings} → Visibility, project features, permissions → {feature}\n"
         f"- the token's user has a role that can read them: {ENDPOINT}/team/svc/-/project_members"
@@ -392,7 +410,9 @@ def test_forbidden_commit_lookup_points_at_merge_requests(gitlab: respx.Router)
     error: typing.Final = _only_service(_collect()).error
 
     assert error is not None
-    assert error.startswith("team/svc: GitLab denied access to merge requests (403). Check that:\n- Merge requests are")
+    assert error.text.startswith(
+        "team/svc: GitLab denied access to merge requests (403). Check that:\n- Merge requests are"
+    )
 
 
 def test_forbidden_project_stops_the_run(httpx2_mock: respx.Router) -> None:
@@ -406,7 +426,11 @@ def test_forbidden_project_stops_the_run(httpx2_mock: respx.Router) -> None:
 def test_network_failure_names_the_project(gitlab: respx.Router) -> None:
     gitlab["tags"].mock(side_effect=httpcore2.ConnectError("down"))
 
-    assert _only_service(_collect()).error == "team/svc: GitLab request for the repository failed (NetworkError)."
+    assert _only_service(_collect()).error == Message(
+        code=MessageCode.GITLAB_UNREACHABLE,
+        params={"project": "team/svc", "resource": "repository", "reason": "NetworkError"},
+        text="team/svc: GitLab request for the repository failed (NetworkError).",
+    )
 
 
 _LIB_FEATURES: typing.Final = (
@@ -435,7 +459,8 @@ def test_project_without_deployments_is_skipped_with_a_warning(
     report: typing.Final = _collect()
 
     skipped: typing.Final = report.services[0]
-    assert (skipped.project, skipped.rows, skipped.error, skipped.warnings) == ("team/lib", [], None, [warning])
+    assert (skipped.project, skipped.rows, skipped.error) == ("team/lib", [], None)
+    assert [item.text for item in skipped.warnings] == [warning]
     assert len(report.services[1].rows) == 5
 
 
@@ -487,7 +512,13 @@ def test_service_without_production_deployment_lists_the_whole_default_branch(gi
         ("1.2.0", 4, f"{ENDPOINT}/team/svc/-/commits/1.2.0"),
         ("1.1.0", 2, f"{ENDPOINT}/team/svc/-/commits/1.1.0"),
     ]
-    assert service.warnings == ["No successful deployment to 'production'; rows run from the first commit of main."]
+    assert service.warnings == [
+        Message(
+            code=MessageCode.NO_PRODUCTION,
+            params={"environment": "production", "branch": "main"},
+            text="No successful deployment to 'production'; rows run from the first commit of main.",
+        )
+    ]
 
 
 @pytest.mark.httpx2(assert_all_called=False)
@@ -497,7 +528,7 @@ def test_service_without_default_branch_has_no_rows(gitlab: respx.Router) -> Non
     service: typing.Final = _only_service(_collect())
 
     assert service.rows == []
-    assert service.warnings == ["Project has no default branch."]
+    assert service.warnings == [Message(code=MessageCode.NO_DEFAULT_BRANCH, text="Project has no default branch.")]
 
 
 @pytest.mark.httpx2(assert_all_called=False)
@@ -530,7 +561,13 @@ def test_long_range_is_truncated_with_a_warning(gitlab: respx.Router) -> None:
     service: typing.Final = _only_service(_collect(max_commits=2))
 
     assert [row.commits[0].sha for row in service.rows] == ["head", "c3"]
-    assert service.warnings == ["Stopped after 2 commits; older changes are omitted."]
+    assert service.warnings == [
+        Message(
+            code=MessageCode.COMMITS_TRUNCATED,
+            params={"max_commits": 2},
+            text="Stopped after 2 commits; older changes are omitted.",
+        )
+    ]
     assert service.truncated
     assert gitlab["commits"].call_count == 1
 
@@ -540,7 +577,7 @@ def test_range_page_larger_than_the_limit_is_trimmed(gitlab: respx.Router) -> No
     service: typing.Final = _only_service(_collect(max_commits=3))
 
     assert [row.commits[0].sha for row in service.rows] == ["head", "c3", "c2"]
-    assert service.warnings == ["Stopped after 3 commits; older changes are omitted."]
+    assert [item.text for item in service.warnings] == ["Stopped after 3 commits; older changes are omitted."]
     assert gitlab["commits"].call_count == 1
 
 
@@ -550,7 +587,9 @@ def test_long_tag_list_is_truncated_with_a_warning(gitlab: respx.Router) -> None
 
     service: typing.Final = _only_service(_collect())
 
-    assert service.warnings == ["Tag list was truncated; some tags may be missing from rows."]
+    assert service.warnings == [
+        Message(code=MessageCode.TAGS_TRUNCATED, text="Tag list was truncated; some tags may be missing from rows.")
+    ]
     assert gitlab["tags"].call_count == 50