JSONPlaceholder MCP Server

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

No annotations are provided, so the description carries full burden. It mentions retrieval and filtering options but doesn't disclose behavioral traits such as whether this is a read-only operation, potential rate limits, authentication needs, or what happens when both parameters are provided. The description is minimal and misses key operational context.

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 a single, efficient sentence with zero waste. It's appropriately sized and front-loaded, directly stating the tool's function without unnecessary elaboration.

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 no annotations, 0% schema coverage, no output schema, and two parameters, the description is incomplete. It lacks details on return values, error conditions, and full parameter usage, making it inadequate for a tool with this complexity. The description does not compensate for the missing structured information.

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 mentions 'filtered by user ID' and 'get a specific todo', which loosely maps to the two parameters, but doesn't explain semantics like how filtering works, whether parameters are exclusive, or default behaviors. This adds minimal value 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 verb ('Retrieve') and resource ('todos'), making the purpose understandable. It distinguishes between retrieving all todos versus filtered/specific ones, though it doesn't explicitly differentiate from sibling tools like 'get_users' or 'get_posts' which might have similar retrieval patterns.

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 implies usage through 'optionally filtered by user ID or get a specific todo', suggesting when to use parameters, but lacks explicit guidance on when to choose this tool over alternatives like 'search_posts' or other get_* siblings. No when-not-to-use or prerequisite information is provided.

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