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

Annotations already declare readOnlyHint=true and openWorldHint=true, covering safety and open-world assumptions. The description adds cost transparency: 'Costs one credit for the company plus one per pulled event; nothing is charged if no company matches.' This is valuable behavioral context—agents can weigh cost implications. It also discloses that resolution can be done via multiple identifiers, and implies partial result behavior when no company matches. No contradiction with 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?

The description is three sentences: first states the core purpose, second lists resolution keys, third explains event filtering and cost. Every sentence earns its place—no fluff, front-loaded with the most important information. It's concise and logically structured.

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 description covers all critical aspects for a tool with 5 optional parameters and moderate complexity: what it returns (timeline components), resolution methods, filtering, and cost. There's no output schema, so the description does a good job conveying return content. It doesn't discuss pagination or limits, but these are not critical for a timeline tool and are likely documented elsewhere. Overall, it's complete enough for an agent to invoke correctly.

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 100%, so parameters are already well-documented. The description adds meaning by clarifying that id, domain, name, and linkedinUrl are alternative identification methods ('Resolve the company by...'), which isn't explicitly stated in the schema descriptions. It also reinforces the include parameter's role and cost implication. This adds value 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?

The description opens with a specific verb and resource: 'Return one company's timeline' and enumerates the contained data (firmographics, investors, funding rounds, acquisitions, executive moves). It also clarifies resolution methods (id, domain, name, LinkedIn URL), distinguishing it from sibling tools like acquisitions or funding_events which focus on specific event types. This is unambiguous and differentiates from alternatives.

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 provides clear context: it returns a comprehensive timeline for a single company and allows filtering event kinds via the include parameter (default all). It doesn't explicitly name alternative tools (e.g., 'use funding_events for funding only'), but it implies this is the one-stop timeline tool versus the more specialized sibling tools. The guidance is sufficient for most agents to select it appropriately.

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