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

Annotations already declare readOnlyHint, openWorldHint, and idempotentHint, so the safety profile is handled. The description adds that results include registration procedure and defining documents and that it covers the full IANA protocol registries index, which is useful behavioral context. However, it doesn't describe ranking beyond what the query schema already says, nor any limitations.

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?

Three efficient sentences: purpose and examples first, then return values and registry coverage. No filler or repetition.

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 search tool with annotations covering safety and an output schema (though not shown in detail), the description provides enough – what it searches, examples, return contents, and scope. It could mention pagination via offset/limit, but that is already in the schema. Minor gap in not stating result ordering beyond what the query parameter already describes.

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 query, limit, and offset parameters are fully documented in the schema. The description just restates that it searches titles and categories, adding no extra syntax or format details beyond the schema.

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 (Find) and resource (IANA protocol registries and sub-registries) with matching scope (titles and protocol categories). It also names the downstream sibling iana_get_registry_records whose inputs it produces, clearly distinguishing it from the lookup_* tools that resolve specific values.

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?

The description implies when to use it (to discover registries by keyword) and examples like 'tls cipher' show how to query. It mentions the relationship with iana_get_registry_records but doesn't explicitly say when not to use it or describe cases where a direct lookup tool would be better.

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