Find MCP - Agentage MCP Directory

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already mark the tool as read-only and non-destructive. The description adds context about the return content (every category, language, license with server counts) and confirms it takes no input. This goes beyond annotations, though it omits potential rate limits or pagination behavior.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is compact and front-loaded: the first sentence states the core purpose, the second gives usage timing, and the final clauses confirm no input and read-only nature. Every sentence earns its place with no filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple no-input, read-only listing tool with an output schema, the description fully covers what is returned, when to call it, and its safety profile. It also addresses the relationship with mcp_search, making it contextually complete.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool has zero parameters, so the baseline is 4. The description confirms 'Takes no input,' matching the empty schema. No further parameter explanation is necessary or possible.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb ('List') and resource ('directory's available filter values'), enumerates the exact contents (category, language, license) and includes counts. It clearly distinguishes itself from sibling mcp_search by establishing itself as the precursor for obtaining valid filter values.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicit guidance states 'Call this BEFORE mcp_search when you intend to filter' and instructs the agent to pass exact, existing values instead of guessing. This directly tells when to use the tool relative to the alternative sibling.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true and destructiveHint=false. The description adds valuable behavioral context: slug canonicalization rules, fallback resolution with `resolved_from`, and error listing candidate slugs. This goes well beyond the structured annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is moderately long but every sentence earns its place: purpose, contents, usage sequence, slug format, fallback behavior, and read-only note. It is front-loaded and well organized with no filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With only one parameter, an output schema present, and annotations covering safety, the description covers all needed context: when to use, how to source the slug, fallback behavior, and read-only nature. No significant gaps remain.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% and the slug parameter's schema description already includes verbatim-from-search guidance, canonical format, and fallback behavior. The tool description adds minimal new meaning beyond this, so baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool fetches one MCP server's complete record by canonical slug, enumerating the contents (description, categories, packages, endpoints, tools, install command, README). It distinguishes itself from mcp_search by noting it provides depth beyond result cards.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly instructs to use this after mcp_search and to call mcp_search first if no slug is available. It also explains the fallback resolution for plain names and error behavior, giving unambiguous when-to-use and when-not-to-use guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Beyond the readOnlyHint/openWorldHint annotations, the description adds ranking behavior ('ranked by text relevance to the query first, then by popularity'), result card contents, and a hard rejection when invalid category values are passed. It also states 'Read-only - never installs or runs anything,' reinforcing the annotation without contradiction.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Though longer than typical descriptions, every sentence carries distinct value: purpose, usage guidance, ranking behavior, return format, integration with siblings, filtering prerequisites, and safety. It is front-loaded with the core purpose and remains tightly structured with no filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's complexity (7 params, search semantics, pagination, sibling interactions) and the presence of an output schema, the description covers all necessary context: what to search, how results are ranked and returned, how to drill down via mcp_get, and filtering prerequisites. No critical operational detail is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% and the schema already provides detailed parameter descriptions (e.g., query guidance to 'Prefer a single distinctive term', category enums, license format). The description adds minor reinforcement by reminding the agent to call mcp_categories and pass labels verbatim, but that is already largely present in the schema. It does not significantly deepen parameter understanding.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb+resource+scope: 'Search the agentage MCP directory ... for servers matching a keyword, optionally narrowed by type, category, language, or license.' This clearly distinguishes it from siblings mcp_get (fetch full details) and mcp_categories (get valid filter values).

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly says 'Use this FIRST whenever the user wants to discover, find, compare, or pick an MCP server' and directs to 'call mcp_get with the slug from a result' for full details, plus to call mcp_categories before filtering. This provides clear when/when-not guidance and names alternatives.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.