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

No annotations are provided, so the description carries full responsibility. It discloses the scope (accepted contacts and pending/decided requests) and the optional status filter, but does not mention whether the operation is read-only, any authentication requirements (beyond the tenant_key schema note), pagination, or rate limits. The 'List' verb implies read-only, but this is not explicitly stated.

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?

The description is a single sentence that front-loads the main purpose (listing contacts/requests) and then explains the optional status filter. It is efficient with no wasted words, though it could be slightly more concise by dropping the redundant 'in either direction' phrase already implied by 'incoming/outgoing.'

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?

Given the tool's simplicity (2 parameters, no output schema, no annotations), the description covers the essential behavior. However, it lacks any mention of the return format (e.g., array of objects) or pagination, and does not explain what 'decided' means in detail. An agent would know what tool to call but not what to expect back, leaving some ambiguity.

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% for both parameters. The description adds minimal semantic value beyond the schema: it reiterates that status filters 'incoming/outgoing' (already in schema) and does not explain tenant_key beyond what the schema says. Since coverage is high, the baseline of 3 applies; the description does not enhance parameter understanding.

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 clearly states a specific verb ('List') and resource ('accepted contacts' and 'pending/decided contact request in either direction'), and it distinguishes itself from siblings like contact_accept, contact_deny, and contact_request by focusing on enumeration rather than mutation. The scope and optional filtering are explicitly defined.

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?

The description implies when to use it (listing contacts/requests) but does not explicitly mention alternatives or exclusions. It doesn't say 'use lookup for a single contact' or 'use contacts_import to add contacts.' While the context suggests it's the default list tool, explicit guidance on when not to use it is absent.

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