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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds valuable context beyond these: it clarifies the access model (public/unlisted open, private requires owner's lp_ API key) and specifies that it returns Markdown source. This goes beyond what annotations provide, so a 4 is warranted.

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 with no wasteful phrases. The first sentence immediately states the core purpose, and the second covers access requirements. Information is front-loaded and every word contributes to understanding. This is an exemplary concise structure.

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 single-parameter read tool with an output schema and comprehensive annotations, the description covers all essential aspects: what it fetches, access conditions, and the API key requirement. The output format is handled by the output schema, and no extra clarifications (e.g., error handling) are needed for such a straightforward operation. It is fully 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 schema covers the only parameter (slug) with a clear description of its meaning. The tool description does not add additional parameter-specific information, but with 100% schema coverage, the baseline of 3 is appropriate. The description's mention of 'https://lucid.page/<slug>' aligns with the schema's URL explanation, offering no extra value.

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 states a specific verb ('Fetch') and a precise resource ('the canonical Markdown source of a page'). It clearly differentiates from siblings like list_docs (which lists documents) and mutation tools like update_doc or delete_doc. The phrase 'canonical Markdown source' leaves no ambiguity about what is returned.

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 provides clear context on when the tool is appropriate by outlining access rules (public/unlisted vs private, with owner's API key). It does not explicitly name alternatives or state when not to use it, but the read-only nature makes it unambiguous that this is the default retrieval tool for a single document. The lack of explicit exclusions is a minor gap.

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