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

Beyond the readOnly/idempotent annotations, it discloses non-obvious behavior: zero cost ('FREE (no credits)'), no provider call, the empty-until-a-snapshot-exists condition, and which sibling triggers auto-capture. This is exactly the behavioral context annotations cannot express.

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?

Front-loads the core definition and ordering, then cost, then the empty-state gotcha. Information-dense and every sentence earns its place, though the third sentence is somewhat packed and could be trimmed.

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?

No output schema exists, so the description carries the burden of describing returns, and it does: the shape (dated authority snapshots), ordering (oldest first), and the empty-state case. An agent has everything needed to call and interpret it.

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 coverage is 100%, so the schema documents both parameters; baseline would be 3. The description adds value by clarifying that `domain` accepts any domain, including 'a tracked competitor', and that the call is scoped to one project+domain, which sharpens how the two required params combine.

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 and resource ('the stored trend of dated authority snapshots for one project+domain') and even specifies ordering ('oldest first'). It is clearly distinguishable from get_domain_overview and capture_domain_authority_snapshot, which it names explicitly.

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?

Explicitly covers when to use it (free read-back of already-captured snapshots) and how to make it non-empty, naming the two alternatives: get_domain_overview auto-captures for the project's own domain, or capture_domain_authority_snapshot for any domain. Nothing is left to inference.

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