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

Annotations already cover safety (readOnly, idempotent, non-destructive, open-world), yet the description adds substantial behavioral context: exact-match domain semantics with a worked example, up-to-5 name candidates with match_confidence thresholds, the returned field set, no-hiring-signal warning, empty-list-instead-of-error contract, the never-billed note, and the signup-link fallback when no key is present. None of this is in the 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?

Front-loaded with the WHEN trigger, then ordered by domain semantics, name semantics, return shape, and edge cases. Every sentence carries distinct, actionable information (exclusivity rule, example, confidence values, error/empty behaviors) 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?

With no output schema, the description fully specifies the return shape (`company_id`, `company_name`, `company_domain`, `country_code`, `coverage_status`), the empty-result contract, the no-key fallback, and the error condition. An agent has everything needed to invoke and interpret 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?

Schema coverage is only 33% (just the deprecated `plane_api_key`), so the description carries the load and does so: it explains the exactly-one-of `domain`/`name` rule, that `domain` accepts a bare host or full URL and matches exactly (with an example), and that `name` returns up to five ranked candidates with confidence scoring.

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+resource ('Find company by domain or name') and immediately distinguishes itself from the siblings that consume its output, naming the `company_id`-dependent tools (`is_hiring`, `get_open_reqs`, `hiring_pulse`, `pre_action_brief`, `watch_company`). It also explicitly disclaims the hiring-signal role and routes to `is_hiring`, so the agent can separate it from every nearby tool without opening a 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?

Opens with an explicit trigger condition ('WHEN you hold a company's website or name but not the `company_id`') and states the bad call conditions ('both or neither is an error naming that rule'). It names the alternative for hiring data (`is_hiring`), giving both when-to-use and when-not-to-use guidance.

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