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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so the safety profile is covered. The description adds an authentication prerequisite and the fact that each contact is returned with its id, which is useful context for chaining calls. No contradictions with 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?

Two short sentences front-load the purpose, then state authentication and what the response provides. No wasted words or repetition of schema details.

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 simple list tool with no output schema and full annotation coverage, the description gives purpose, auth prerequisite, and the id return value needed for subsequent operations. It omits pagination/order/edge-case behavior, but that is minor for this complexity.

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 has 100% coverage: 'search' is described as matched against name/email/organization, and 'sessionKey' details the in-chat device flow vs OAuth. The description only reiterates 'optionally filtered by a search term' and adds no parameter-specific meaning beyond the schema, so 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 ('List'), resource ('contacts'), and scope ('for the authenticated user'), plus an optional search filter. It also hints at downstream use by mentioning ids feed into getContact/updateContact/deleteContact or domain registration. It does not explicitly call out the sibling getContactsForDomain, leaving a minor ambiguity, so 4 rather than 5.

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?

Says it requires authentication and that the returned ids are intended for use in other contact operations or domain registration, which tells an agent when to call this first. It does not mention alternatives like getContactsForDomain or conditions for when not to use this tool, so it falls short of full guidance.

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