get_verified_user

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

readOnlyHint=true already covers the safety profile, and the description adds real context beyond it: the tool requires a Proof account, depends on an environment variable being set with a server restart, and is explicitly not opened by start_login. Return shape and pagination are not described, but the access preconditions are actionable.

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-loads the core purpose in one sentence and segregates the access caveat into a labeled second block. Efficient overall, though the restart instruction is slightly more procedural detail than the selection task strictly needs.

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 one-parameter read tool with full schema coverage and readOnlyHint annotations, the description supplies everything needed to attempt a correct call, including the non-obvious account prerequisite. No output schema exists, but the return format is mentioned in prose ('and their verifications').

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% and there is only one parameter, so the baseline is 3. 'By external user ID' frames the lookup but adds no format, validation, or resolution detail beyond what the schema already provides.

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 (get), resource (a single verified user plus their verifications), and lookup key (external user ID). The word 'single' implicitly contrasts with list_verified_users, but that sibling is never named, so differentiation rests on inference rather than explicit statement.

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?

Provides a prerequisite gate ('needs a Proof account, set PROOF_API_KEY and restart') and a useful exclusion ('start_login does NOT open this tool'), which tells the agent it cannot be unlocked via that flow. However, it gives no positive when-to-use guidance and never routes to alternatives such as list_verified_users or get_verification.

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