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

Goes well beyond the readOnly/idempotent annotations by disclosing Pro+ gating, the cost model (free read vs credit-spending scan), and the freshness contract: snapshot is null and stale=true until one exists or is older than a day. This is exactly the behavioral context an agent needs to interpret the response.

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-loaded with what is returned, then constraints and routing. Dense and information-rich with no filler sentences, though the parenthetical definition of `stale` and the semicolon-chained clauses make it slightly cramped rather than crisp.

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?

With no output schema, the description carries the return-shape burden and does so by enumerating the result fields (query, answer snippet, source URL, competitor landscape). Combined with the Pro+ gate, snapshot freshness rules, and the scan/poll alternative, an agent has everything needed to call it correctly.

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 all four parameters are already documented in the schema itself. The description reinforces includeHistory (trend over past scans) and the model filter, but adds no syntax or format detail beyond what the schema provides. Baseline 3 applies when the schema does the heavy lifting.

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 (returns AI citation/mention data for a site) with the full granularity of what's covered: totals, citation rate, by-model breakdown, citing sources, competitor landscape, individual mentions. It also implicitly distinguishes itself from run_ai_mentions_scan by naming that sibling for fresh scans.

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 says when to use it (read the stored snapshot, free, Pro+ only), when not to expect fresh data ('nothing is scanned by this tool'), and routes to the alternative workflow ('Run a fresh scan with run_ai_mentions_scan, then poll get_job kind=ai_scan'). 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.