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

With no annotations, the description carries the full burden. It discloses useful behaviors: exclusion of scaffold-tier peers and the guarantee that a 'coverage_status' is always present. It also notes the deterministic nature of the one-liner. However, it does not discuss other aspects such as read-only nature, error conditions, or latency, though these are less critical for this type of tool.

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 three sentences with no wasted words. It front-loads the primary use case, then adds the exclusion behavior and the coverage_status guarantee. Every sentence contributes meaningful information, making it an excellent example of conciseness.

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 the simple 2-param schema, no output schema, and the tool's read-only nature, the description is quite complete. It covers what the tool returns (competitor set, peer snapshots, one-liner, coverage_status), its key limitation (scaffold tier exclusion), and the deterministic quality. It could go deeper on the shape of the return value, but the 'coverage_status' mention provides crucial context.

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 fully documents both parameters (brand and limit) with clear descriptions, so baseline is 3. The tool's description does not add any additional meaning to the parameters themselves; it focuses on the output and use case rather than parameter usage or interpretation.

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 what the tool provides: a brand's competitor set, peer momentum snapshots, and a deterministic competitive-position one-liner. It also differentiates from siblings by mentioning the unique 'coverage_status' and exclusion of scaffold-tier peers. However, it lacks an explicit verb like 'get' or 'retrieve', instead phrasing it as a use case ('Use this when...'), which is slightly indirect.

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 explicitly says 'Use this when an agent needs...', giving clear context for when the tool is appropriate. It also adds a limitation ('Excludes peers without real signal coverage'), which helps in deciding when not to use it. However, it does not mention alternative sibling tools or directly state when to prefer another tool.

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