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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the description correctly aligns with them and adds extra context: 'no auth', the counting start date, and the exact time windows and metrics returned. This goes beyond the structured annotations without contradicting them.

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?

Four sentences, each earning its place: purpose and motivation, with-path behavior, without-path behavior, and access/data caveats. It is front-loaded with the key purpose and contains no filler.

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 read-only stats tool with no output schema, the description adequately explains both modes' return content, the time windows, the leaderboard ranking behavior, and the access constraints. Remaining details like limit and sort options are already covered in the input schema, so nothing critical is missing.

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 input schema already documents all four parameters with 100% coverage, so the baseline is 3. The description usefully explains the path-dependent behavior and gives an example, but it adds little new meaning for days, sort, or limit beyond what the schema already states.

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 a specific verb/resource: it returns public traffic and likes for rebuilt apps, with the explicit goal of measuring whether a rebuild is used. It also clearly distinguishes the two modes: per-app stats with 'path' vs a ranked leaderboard without 'path', so an agent knows exactly what outcome to expect.

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?

Gives clear contextual guidance: use 'path' to get a single app's stats and omit it for the ranked leaderboard. It does not explicitly compare against sibling tools like bb_search_rebuilt_apps, but the usage context is clear enough for an agent to know when this tool is appropriate.

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