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

Annotations already cover read-only/idempotent/open-world, yet the description still discloses substantive behavior: which decision states are included (approved/refused/withdrawn), that unknown decisions are excluded, and that coverage/freshness are incomplete and unverified. The explicit prohibition on inferring approval from missing status is exactly the kind of context annotations cannot carry.

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 easy to scan and front-load the purpose. It is dense and slightly longer than strictly necessary, but nearly every sentence carries actionable content.

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 5-parameter, nested-object tool with an output schema, this covers location resolution, decision-state filtering, coverage caveats, parameter ranges, and the chaining contract. An agent has everything needed to call it correctly and interpret the results.

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?

It supplies concrete ranges (radius 250–1000m, limit 1–10) and clarifies that proposal_text acts as a literal string filter on returned reference/address/description rather than a semantic query. It also explains the site_ref chaining contract. Coverage is 60%, and the radius_meters and limit units are covered, though the tension with the schema's 'bias the precedent search' wording for proposal_text leaves a small ambiguity.

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 ('retrieve'), a specific resource ('explicitly decided records'), and a bounded scope ('national planning-application sample for a resolved England site'). It implicitly separates itself from policy/comparables siblings via the limitations clause, but never names a sibling explicitly, so it lands just short of 5.

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?

'When to use: to locate application references for manual decision and policy verification' gives a clear triggering context, and the Limitations block effectively defines when not to rely on the output. It stops short of naming an alternative tool for the cases it excludes.

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