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

Annotations cover the safety profile (readOnlyHint, openWorldHint), but the description adds genuinely non-redundant operational context: a cost of 5 credits per call and that misses, errors and evidence-free answers are free. That pricing/enforcement detail is not derivable from annotations or schema, though it stops short of describing latency, freshness, or the exact response shape.

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 dense sentences, front-loaded with the outcome, then usage, then exclusions and cost. No filler, no repetition of the name or title, and the most decision-relevant information (what it returns, when to use it) comes first.

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?

Despite having no output schema, the description enumerates the return fields, names the deciding alternatives, and discloses cost. For a three-parameter read tool with full schema coverage, nothing an agent needs in order to select or call it 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 description coverage is 100%, so the schema already documents name, domain and company, including the 'strongly recommended' note on domain. The description only restates that passing domain or company improves matching, adding motivation but no new syntax, format, or precedence rules beyond what the schema provides. 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 ('Returns a professional profile for one named person') and enumerates the returned fields (title, seniority, department, experience, skills). It also names the two sibling tools it is not, so an agent can route without opening any 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?

Explicit when-to-use ('when you already have a full name and want to confirm or fill in role details') plus explicit exclusions with named alternatives: apione_people_search for finding people, apione_email_find for emails. Both the condition and the alternatives are spelled out.

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