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

Beyond the readOnlyHint annotation it discloses hybrid keyword+semantic retrieval, prompt-injection sanitization, the 25-hit cap, the exact per-hit return fields, `returned` and `indexes_unanswered` in the payload, and the notable absence of a total match count. That is substantive behavior an agent cannot infer from 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 one-sentence purpose before the operational detail, and the bulleted index lists are high-value rather than filler. Slight redundancy in restating read-only/sanitization and the trailing examples, but nothing is wasted enough to hurt.

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?

No output schema exists, yet the description specifies the return envelope and per-hit fields, the result cap, and the timeout signaling. Combined with annotations and a fully described schema, an agent has everything needed to call it and interpret the response.

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 schema already documents all three parameters; the description goes further by explaining what each index actually contains (iocs, adversaries, cisa_kev, pulses, blog vs. the four archives) and how naming indexes changes scope. The semantics of `limit` beyond the schema max are not expanded, keeping it just short of 5.

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 (searches) and resource (threat-intelligence records), enumerates the record types covered, and explicitly excludes general programming/web content. An agent can distinguish it from siblings like enrich-ioc or the kev-* tools from the description alone.

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 explicit when-to-use: default index set is named, archive indexes are 'searched only when named', and the 'holds no general programming or web content' line rules out misuse. Three worked examples show query and indexes combinations that select the right behavior.

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