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

Annotations already declare readOnlyHint=true, idempotentHint=true, and openWorldHint=true, so the safety profile is covered. The description adds the api_key requirement nuance (optional on public, required on /mcp/mcp), which is real behavioral context beyond annotations. But it doesn't describe pagination, result ordering, or behavior when no matches are found.

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?

Two concise sentences deliver the core purpose and an important edge case about auth. No fluff. Slightly terse given the behavioral constraints, but overall efficient and front-loaded.

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?

The search tool has 4 params, 0% schema coverage, and an output schema present. The description covers the main action and the api_key nuance but doesn't clarify query semantics or ranking_id meaning. Given the output schema exists and annotations cover safety, this is adequate but not complete.

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 some burden to explain parameters. The description clarifies the api_key parameter's conditional necessity, which compensates slightly. But it doesn't explain limit semantics, query behavior, or ranking_id beyond what the schema provides. The api_key note is the only value-add over 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?

Description states a specific verb ('find') and resource ('entities by name substring within a ranking'), which clearly identifies what the tool does. It doesn't explicitly distinguish from siblings like aimrank_list_domain_entities, but the 'substring search within a ranking' framing is enough to differentiate it from pure listing 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?

The description gives an implementation detail about api_key on the public endpoint vs /mcp/mcp, but doesn't say when to prefer this tool over siblings like list_domain_entities or discover_public_rankings. No guidance about when to use search vs list, or what contexts warrant a substring query versus an exact lookup.

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