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

Annotations already declare readOnly/idempotent/openWorld, so safety is covered. The description adds genuinely non-structured context: the call "costs 5 credits" — the single most important operational fact for an agent deciding whether to call it. It stops short of noting data freshness or rate limits.

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 short sentences: what it returns first, then cost, then input format and parameter guidance. Every sentence carries information an agent needs, with no filler.

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?

Output schema exists so return shape needn't be described; cost, input format, and the optional-parameter rationale are all present. Only gaps are data recency and how to choose this over sibling company tools.

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 must carry the load, and it does: domain is constrained to a bare web domain with a concrete example and an explicit anti-pattern (LinkedIn URL), and company_name's purpose (disambiguation when the domain is shared or ambiguous) is spelled out. Both of the two parameters gain meaning not present in 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 and resource ("Fetch a company's Crunchbase funding history by domain") and enumerates the returned fields (amount raised, round type, announcement date). It is distinguishable from get_company_profile by scope, but the description never names that sibling to make the boundary explicit.

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 the concrete input format constraint ("Takes a web domain such as `stripe.com`, not a LinkedIn URL") and explains when to bother with the optional company_name. It does not, however, say when to prefer this over search_companies or get_company_profile for company data.

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