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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds the id format behavior, but does not disclose what the response contains, error behaviors, or any limits. Given the simplicity and read-only nature, this is adequate but not rich.

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 two sentences with zero waste. The primary purpose and formats are front-loaded, and the alternative tool is mentioned in a second sentence. Every word serves a clear function.

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 tool with a single parameter and no output schema, the description is fairly complete. It clarifies the id format and points to alternatives for direct access. It does not describe the return value, but given it's a fetch of a search result, the agent likely has prior context from the search tool. A minor gap is the lack of explicit mention that this id originates from the search 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 thoroughly explains the 'id' parameter by defining two valid formats with placeholders, which is essential for correct usage. This adds significant meaning beyond the schema's bare 'string' type.

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 a search result by id, and explicitly defines the two id formats: a project overview ('<projectId>') or a file ('<projectId>:<path>'). It distinguishes itself from siblings by noting that read_file/list_files provide more detail for direct access, making the purpose unmistakable.

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 gives clear context for when to use this tool vs. alternatives by stating 'For direct access to a known file or project, read_file/list_files give more detail.' This implies fetch is meant for search result ids, not known paths. While it doesn't enumerate other alternatives, the primary distinction is covered.

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