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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely non-obvious behavior: defanging is refanged before matching, matching is exact with a case-insensitive fallback, and results come newest-first. The one gap is what happens when no report matches.

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 question in the first sentence, then matching behavior, then return shape — a sensible order with little waste. The inline formatting reference to `input` is slightly cryptic but does not bloat the text.

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 full schema coverage, complete annotations and an output schema, the description covers nearly everything an agent needs. Only the no-match/empty-result behavior is left unspecified, which is a minor omission for a read-only lookup.

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 coverage is 100%, so the baseline is 3; the description earns extra credit by explaining that defanged values are refanged before lookup while `input` echoes the value as given, and that results are newest-first capped at max_matches. It adds real semantics on top of the schema rather than restating it.

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 — 'Check whether one IOC ... appears in Rösti's threat-intelligence reports' — and the singular 'one IOC' implicitly separates it from the plural lookup_iocs and search_iocs siblings. It never names those alternatives explicitly, so an agent must infer the split from the singular/plural distinction.

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?

Usage is implied by the phrasing 'Check whether one IOC ... appears,' which suggests a single-value verification use case. There is no explicit when-to-use/when-not guidance and no named alternative for batch or fuzzy lookups, even though lookup_iocs and search_iocs sit right beside it.

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