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

With no annotations, the description must convey behavioral traits on its own. It only mentions the access requirement and that start_login does not open the tool. It does not disclose whether the update is partial or full (e.g., whether passing only name preserves other fields), the effect of null name, or what happens to existing channels when a new array is provided. For a mutation tool, this is insufficient.

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 compact and front-loaded with the core purpose. The access note is a separate block, which is useful but slightly tangential. Overall, it is efficient with no redundant phrasing.

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 no output schema and no annotations, the description carries the full burden of explaining usage. It lacks key details such as whether the update replaces the entire channels array, whether only specified fields are updated, and the behavior when an invalid id is provided. The tool has multiple parameters and a nested channels structure, so more guidance is needed for correct invocation.

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 the schema already explains each parameter (e.g., 'New name (null to clear)', 'Updated channels', 'Updated timeout in seconds'). The description merely lists the same fields without adding nuance or clarifying interactions between them, so it adds no value beyond the schema.

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 the tool updates a HITL config and lists the exact fields that can be changed (name, channels, timeout). This distinguishes it from sibling tools like create_hitl, delete_hitl, and get_hitl without needing to compare schemas.

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 provides only an authentication prerequisite ('needs a Proof account... start_login does NOT open this tool') but does not explain when to use this tool versus alternatives such as create_hitl or update_settings. There is no explicit guidance on when to choose this tool over a sibling.

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