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

Annotations already declare readOnly/idempotent/non-destructive/openWorld, and the description adds real behavior on top: the call returns only a reviewable request and site_ref rather than findings, it performs no web search, search depends on host availability, and point/country inputs 'do not prove parcel or legal jurisdiction'. Those limitations are exactly the kind of 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?

Labeled sections (Purpose / When to use / Returns / Limitations / Parameter guidance / Chaining) make it scannable and front-loaded, with no filler sentences. The 'Returns' summary and the final chaining sentence overlap somewhat, and since an output schema exists the return-value prose is partly redundant.

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 a 6-parameter tool with a deep nested site_ref object and an output schema, the description covers the essential agent-facing contract: trigger, output type, safety posture, chaining, and jurisdiction caveats. Gaps remain around radius_meters/country_code and how an invalid or stale site_ref is handled.

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 description coverage is only 17%, so the description must carry parameter meaning. It does cover the core pair ('supply question and location or returned site_ref') and the site_ref chaining contract, but radius_meters, country_code, and the address-vs-coordinates tradeoff are never explained in prose.

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: 'prepare a site-bound research request for the current conversation', and explicitly separates it from present_site_research ('Use present_site_research after obtaining cited findings'). The one soft spot is jargon like 'site-bound research request', but the 'Returns ... with no researched findings' line pins down what the agent actually gets.

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?

A dedicated 'When to use' line gives an explicit trigger ('when a user asks to research a global site question'), and the handoff to present_site_research plus the 'show explicit gaps if search is unavailable' fallback covers the downstream path. It stops short of telling the agent when to prefer analyze_site or plan_site_intelligence over this tool, so 4 rather than 5.

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