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

Annotations already declare read-only, idempotent, non-destructive, closed-world, but the description adds substantial non-obvious behavior: a fixed 25-credit cost, UK-only coverage, and — critically — the `sections_degraded` contract with its four absence kinds (`not_found`, `no_certificate`, `not_available`, `error`) and the instruction to report what did not answer. That is rich, actionable disclosure beyond the annotations.

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 the core value proposition, then the operational warning, then cost/domain/key. Three short paragraphs, each earning its place. Slightly dense in the degradation paragraph but no filler.

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?

An output schema exists, so return shape needn't be restated. The description covers the remaining agent-critical facts: what it composes, how sections degrade, cost, geographic scope, and how to obtain the required key. Nothing needed to call it correctly is missing.

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 0%, so the description carries the burden. It explains the `uprn` parameter well (UPRN-keyed, not address, with the resolution path), but says nothing about `include_precedents`, leaving one of two parameters undocumented in both schema and 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 composed resource — 'everything we hold about one property, as one document' — and enumerates the sections it bundles (summary, lease, risk report, rental estimate, energy, planning). The clarifying line 'Each section is the standalone tool of the same name with the same receipts' sharply distinguishes it from the property_summary / property_risk_report / property_lease siblings.

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 a concrete prerequisite workflow: narrow with free `address_autocomplete`, then resolve via `address_resolve` to obtain a UPRN, since it is keyed on UPRN not address. Also implies the cost trade-off (cheaper than sections bought separately). It does not explicitly state when NOT to compose versus calling a single section tool, which keeps it from a 5.

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