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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), but the description adds context those annotations cannot: no match returns an empty list rather than an error, only companies with a public page are searched, one call consumes a quota unit (Free keys have a daily MCP cap), and a rejected argument costs nothing. Cost and failure-mode disclosure is genuinely valuable behavioral information.

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 purpose and routing, then labeled 'Parameters:' and 'Behavior:' sections. Despite packing purpose, alternatives, examples, and quota semantics, every sentence earns its place with no repetition of the schema or annotations.

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 two-parameter, read-only search with an output schema, everything an agent needs is present: what it searches, what it returns, what it does not return (non-public companies), empty-result semantics, quota cost, and the sibling to use for adjacent needs. Return-value detail is correctly left to the output schema.

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, but the description goes beyond the schema for 'query' by giving concrete multilingual examples (Toyota, トヨタ, 7203) that clarify what 'alias or ticker in any of the three languages' actually accepts. The 'locale' parameter is left to the schema, which documents it adequately, so this is not a full 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 (search) and resource (AiSeek's public companies) with the matching dimensions (name, alias, ticker) and the exact result shape (up to 10 matches, most active first, with slug, country, listings, page url). It explicitly distinguishes itself from siblings get_company and search_changes, so an agent can route without opening any schema.

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?

Explicit when-to-use routing: 'Use it to find a company's slug for get_company; for news about a company use search_changes with its name.' It names both alternatives and the condition that selects each, leaving nothing to inference.

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