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

With readOnlyHint already declaring the safe-read profile, the description adds genuine non-obvious behavior: the auth requirement and the counterintuitive warning that start_login does not unlock this tool. It also previews the returned fields. It stops short of covering error cases or whether an unknown ID returns empty vs. raises.

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 blocks, both front-loaded: purpose and return value first, then the access prerequisite. No filler sentences, though the auth note could be tightened slightly.

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?

With no output schema, the description compensates by naming the return payload. Combined with the readOnly annotation and the auth prerequisite, an agent has everything needed to call this correctly: what it does, what comes back, and what access it requires.

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 the single 'id' parameter, so the schema already documents it. The description adds only the implicit notion that the ID refers to an existing confirmation and nothing about format or sourcing. Baseline 3 when the schema carries the parameter detail.

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 ('Get a confirmation by ID') and even enumerates the return payload (status, response, proof token). This distinguishes it from list_confirmations and create_confirmation by the ID-based lookup, though it never names those siblings explicitly.

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?

It gives a real prerequisite ('needs a Proof account', authenticate the client, and start_login does NOT open this tool), which is useful gating context. However, it offers no routing guidance among the many related siblings such as list_confirmations, wait_for_confirmation, or get_confirmation_approval_link, so when-to-use versus alternatives remains implied.

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