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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered; the description still adds real context by disclosing the response shape (held/missing/expiring), the home-country fallback behavior, and the scope caveat 'readiness guidance, not legal advice'. It does not cover auth requirements or rate limits, so it stops short of a full 5.

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?

The trigger condition is front-loaded before the return description, exclusions and example. The first sentence is long and carries a list of country-specific examples that overlaps the schema's own country description, so it is slightly heavier than needed but still efficient.

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 an output schema present and annotations covering the safety profile, the description only needs to supply the trigger, scope and routing caveats — all of which are present. Nothing an agent needs in order to select and invoke this tool 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 100%, so all four parameters (including the sector enum and the country fallback rule) are already documented and the description largely restates them. Its country examples and the illustrative JSON add light invocation value, but not enough to exceed the baseline 3.

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?

Specific verb+resource (check bid readiness for one tender or in general) with a stated output ('Returns what is held, missing or expiring'). It explicitly carves out what it is not for (Companies House look-ups, tax questions), which separates it from siblings like find_company and avoids collisions with the bid-drafting tools.

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?

Opens with an explicit trigger ('Use this when the user wants to know what they're missing before bidding'), covers both modes (single tender vs general check) and states that a general check falls back to the home country. It also gives clear when-not guidance ('Not for Companies House look-ups or tax questions'), leaving little to inference.

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