get_index_stats

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

No annotations provided, so description carries full burden. It details the return dictionary structure and fields, indicating it is a read-only operation. It does not mention performance or side effects, but for a stats tool this is sufficient. No contradictions.

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?

Description is front-loaded with 'USE THIS TOOL' and structured into when/why, args, returns. Every sentence adds value; no fluff or repetition. Length is appropriate.

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 one parameter and stated output schema existence, the description covers all necessary aspects: purpose, usage, parameter, and return structure. It is complete for the tool's complexity.

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 has 0% description coverage for parameters; the description compensates by clearly stating 'directory: Path to the project directory.' This adds meaning beyond the schema's minimal type definition. For one parameter, this is adequate.

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 explicitly states the tool's purpose: to get comprehensive statistics about the code index. It lists specific metrics like file counts, symbol distributions, and database size. It distinguishes itself from siblings by noting what not to use it for (check_index_status, search_code).

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?

Provides clear when-to-use scenarios: understanding index, debugging search quality, checking freshness, monitoring database. Also gives explicit when-not-to-use examples and directs to alternative tools.

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