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

Annotations cover safety (readOnly, idempotent, non-destructive), and the description adds non-obvious behavior on top: the per-call credit cost, UK-only scope, and the exact degradation semantics (unsupplied half reads `not_available` with a reason rather than empty, plus the sections_degraded signal). This is context the 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-loaded purpose sentence, then a clearly emphasized scope warning, then operational notes (degradation check, region, cost). Structure is excellent and nearly every sentence earns its place; the description is a touch long, but the complexity of a multi-source composite report justifies most of it.

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 composite report tool with an output schema already documenting return shape, the description supplies the missing pieces: region constraints, cost, scope keying, and the interpretation guidance for sections_degraded. Nothing needed to invoke it correctly is absent aside from the sector value set.

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?

With 0% schema coverage the description must explain parameters, and it does so for the two critical keys: lad_code is a GSS local-authority code (with a resolver pointer) and postcode_district drives the listing lane, and it stresses they are not interchangeable. The `sector` parameter (default 'ALL') receives no explanation of accepted values, leaving one of three params undocumented.

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 composed artifact and enumerates exactly what it contains (sourcing readiness, commercial capital and rent indices, planning decision record, live listing stock). An agent can distinguish this composite document tool from siblings like market_profile or commercial_market without opening any schema.

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?

Gives strong operational context: UK only, 25 credits, use area_resolve to obtain a lad_code, pass both scopes to fill every section, and check sections_degraded before calling the document complete. It references property_report for shared behavior but does not explicitly state when to prefer this tool over a narrower sibling, keeping it short of a full 5.

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