Lulu Registry MCP

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

Annotations already mark the tool as read-only. Description adds the return payload structure (install commands, transports, categories, registries, trust score) and clarifies the slug comes from search_mcps. Minor gap: no mention of not-found behavior or case sensitivity, but acceptable for a read-only lookup.

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?

Two sentences, front-loaded with the core purpose, followed by a compact list of included data and an explicit usage direction. Every phrase earns its place with no redundancy.

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 one required parameter, a read-only annotation, and an output schema, the description covers what the tool does, what it returns, and when to use it. It gives the agent everything needed to select and invoke the tool correctly.

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 provides only 'slug' as a string with no description (0% coverage). Description compensates by explaining what the slug is (as returned by search_mcps) and that it targets a single server, adding necessary context for correct invocation.

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?

States it provides full details for a single MCP server by slug, listing the specific content fields and linking to search_mcps for discovery. This distinguishes it clearly from the sibling search tool.

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 directs to use after search_mcps when the user wants to install or inspect a specific server, giving a clear workflow and contrasting with the alternative.

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?

The annotation only provides readOnlyHint=true, and the description adds valuable behavioral context: it searches multiple registries, deduplicates results, ranks by a trust score, and returns install one-liners and links. This goes beyond the annotation's safety disclosure. However, it does not mention any potential limitations or rate limits, so it doesn't fully maximize transparency; but it significantly enriches the read-only intent.

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 well-structured, starting with the core function, then usage guidance, return value summary, and parameter details. Every sentence adds value and the information is front-loaded.

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 moderate complexity, an output schema exists, and the read-only annotation is present, the description provides sufficient context: what it searches, how results are ranked, what it returns, and parameter usage. No critical gaps are apparent; it is complete for an agent to decide when and how to invoke the tool.

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 0%, so the description must compensate. It explicitly explains 'category' (narrows, with examples) and 'limit' (caps results 1-10, default 8). The 'query' parameter is not explicitly described, but its purpose is clearly inferred from the search context and examples. Overall, it adds meaning beyond the bare schema.

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's function: 'Search every major MCP registry at once' with specific registries named. It distinguishes from sibling 'get_mcp' by focusing on search/find across multiple sources, and provides concrete example queries. This is a specific verb+resource+scope.

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?

The description explicitly says 'Use whenever you need to FIND an MCP server for a capability' and provides example use cases. It gives clear context for when to use the tool, but does not explicitly mention when not to use it or name an alternative (e.g., get_mcp for retrieving specific server details). Therefore, it lacks the explicit exclusion/alternative guidance needed for a 5.

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