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

Annotations already flag readOnly/idempotent/openWorld, but the description adds the facts that actually change agent behavior: a cost of 50 LeadBoxer credits per profile found, and that nothing is charged on a miss. It also discloses that optional hints improve match rates, which is not recoverable from 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 core purpose and returns, then constraints and cost, with zero filler sentences. The parenthetical 'reverse email lookup, contact enrichment' mildly duplicates the opening phrase, keeping it just short of 5.

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 no-output-schema tool, the description enumerates the returned profile fields (name, headline, LinkedIn URL, seniority, function, location, languages, work history), so the agent knows what it gets back. Cost, hit/miss billing, and exclusion scope are all present; nothing material is missing.

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% and the schema already labels every parameter as optional hints 'to improve matching', so the description's 'Optional name and company hints improve matching' largely restates it. Baseline 3 is appropriate; the description adds consolidation but no new parameter semantics.

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 states a specific verb+resource ('Email to person… reverse email lookup'), enumerates the returned fields, and explicitly separates itself from lookup_domain ('For the company's firmographics, call lookup_domain'). It also states a negative scope boundary ('Does not find or verify emails'), so an agent can place the tool precisely among its siblings.

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?

Concrete usage contexts are given ('enrich new sign-ups, leads and CRM contacts'), the alternative for company data is named with the exact routing condition, and the exclusions are stated. Nothing about when to call this versus lookup_domain is left to inference.

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