fix: change safesearch parameter type from string to number

[Copilot]

MCP SDK validates tool arguments against the JSON schema before the handler runs. safesearch was defined as type: "string" with enum: ["0", "1", "2"], but LLMs send numeric values, causing schema validation to fail:

Failed to parse arguments for tool "searxng_web_search": params.safesearch is not of a type(s) string params.safesearch is not one of enum values: 0,1,2

Changed safesearch to type: "number" with enum: [0, 1, 2] across the stack:

• src/types.ts — Schema type string → number, enum ["0","1","2"] → [0,1,2], TypeScript type updated
• src/search.ts — Function signature safesearch?: string → number, validation against numeric enum, .toString() for URL param serialization
• src/resources.ts — Help text updated to reflect numeric values
• __tests__/unit/search.test.ts — Test passes numeric 1 instead of string '1'

// before
safesearch: { type: "string", enum: ["0", "1", "2"], default: "0" }

// after
safesearch: { type: "number", enum: [0, 1, 2], default: 0 }

This aligns with the SearXNG API (which accepts numeric safesearch) and the README (which already documented it as number).

Original prompt

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This section details on the original issue you should resolve

<issue_title>Issue with parameters</issue_title>
<issue_description>> Failed to parse arguments for tool "searxng_web_search": params.safesearch is not of a type(s) string params.safesearch is not one of enum values: 0,1,2

<tool_call>searxng_web_search <arg_key>query</arg_key> <arg_value>top headlines</arg_value> <arg_key>pageno</arg_key> <arg_value>1</arg_value> <arg_key>time_range</arg_key> <arg_value>day</arg_value> <arg_key>language</arg_key> <arg_value>en</arg_value> <arg_key>safesearch</arg_key> <arg_value>1</arg_value> </tool_call>

Looks like there is a casting issue with the MCP server.</issue_description>

<agent_instructions>Probably a parameter validation or an API call issue. Please check SearXNG API call documentation for details</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes Issue with parameters #42

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[ihor-sokoliuk]

@copilot, what parameter type does the SearXNG server API endpoint expect to receive? Is it a number or a string?

[Copilot]

@copilot, what parameter type does the SearXNG server API endpoint expect to receive? Is it a number or a string?

The SearXNG /search API expects safesearch as an integer value (0, 1, or 2) per the official docs. Since it's sent as an HTTP query parameter (e.g., ?safesearch=1), it's technically a string on the wire, but the API semantically treats it as a number.

Our code handles the conversion correctly at search.ts:72 — we accept a number from the LLM via the MCP schema, then call .toString() when setting the URL search parameter. This matches how pageno (also a number) is already handled on line 58.

[Copilot]

Pull request overview

This PR fixes MCP tool argument schema validation failures by changing the safesearch parameter from a string enum ("0" | "1" | "2") to a numeric enum (0 | 1 | 2) throughout the SDK surface and implementation, aligning with typical LLM outputs and the SearXNG API.

Changes:

• Update searxng_web_search input schema and TS types to treat safesearch as a number enum.
• Update performWebSearch to accept numeric safesearch, validate it against [0,1,2], and serialize it for URL query params.
• Update help text and unit test to use numeric safesearch.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
src/types.ts	Switches schema/type for safesearch to numeric enum in the tool input schema and TS arg typing.
src/search.ts	Updates performWebSearch signature and URL param construction for numeric safesearch.
src/resources.ts	Updates usage/help text to document numeric safesearch values.
__tests__/unit/search.test.ts	Adjusts test callsite to pass numeric safesearch and still assert correct URL serialization.

Comments suppressed due to low confidence (1)

src/types.ts:24

• isSearXNGWebSearchArgs now advertises safesearch?: number, but the guard only validates query and will return true even if safesearch is provided with a non-number type. This makes the type predicate unsound and can lead to silently ignoring user-provided safesearch values at runtime. Consider extending this guard to validate (and ideally range-check) optional fields like pageno, time_range, language, and safesearch when they are present.

export function isSearXNGWebSearchArgs(args: unknown): args is {
  query: string;
  pageno?: number;
  time_range?: string;
  language?: string;
  safesearch?: number;
} {
  return (
    typeof args === "object" &&
    args !== null &&
    "query" in args &&
    typeof (args as { query: string }).query === "string"
  );

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[Copilot]

After changing safesearch to a number, the existing logging code inside this function uses a truthiness check (safesearch ? ...) when building searchParams, which will treat the valid value 0 as “not set” and omit it from logs. Use an explicit safesearch !== undefined check so 0 is logged correctly.