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

Annotations already cover safety (readOnlyHint=true, destructiveHint=false, openWorldHint=false), but the description adds genuinely useful operational context beyond them: the 100-domain cap, the 1 db credit charge only when matches are found, and the account requirement. It does not disclose failure modes or partial-match behavior, so it falls short of 5.

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 the core action, then return fields, use case, limits, cost, and prerequisites in a logical order. Each sentence carries information, though the marketing-tinged framing ("funding intel", "cross-reference workflows") is slightly padded.

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?

No output schema exists, so the description carries the burden of describing return values and does so explicitly (match status, funding amount, latest round, investor IDs, sectors, founded date, HQ country). Combined with the limits, cost model, and auth requirement, an agent has everything needed to invoke it 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?

With only one parameter and 100% schema description coverage, the schema already documents accepted domain formats and the 100 max. The description restates the same domain-array concept without adding format or edge-case detail beyond the schema, so the baseline 3 applies.

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: bulk-matching an array of advertiser/company domains against a startup database, and the description clearly distinguishes it from single-lookup siblings like get_startup_by_domain or get_investor_by_domain. The enumerated return fields make the operation unambiguous.

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 a concrete, explicit use case ("what % of Google Ads / Taboola / Outbrain advertisers are VC-backed") that tells the agent exactly when this tool is the right choice over siblings. It stops short of naming exclusions, e.g. that single-domain lookups or other enrichment tools should be used instead.

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