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

Annotations declare destructiveHint=true and idempotentHint=true, yet the description never mentions that this mutates existing data, whether omitted fields are preserved or cleared, or that the operation is idempotent. For a destructive mutation, the description adds essentially nothing beyond the annotations' safety profile.

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, front-loaded sentences with no filler. The second sentence carries a real constraint, though the description is arguably under-specified rather than optimally concise.

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 destructive, idempotent mutation with no output schema, an agent still lacks key facts: what happens to unspecified fields, whether the update is partial or full, and what a successful call returns. The description is too thin to cover 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 description coverage is 100%, so the baseline is 3. The description's 'at least one field' note reinforces that name/referer are optional but adds no format or semantic detail beyond what the schema already documents (e.g., referer scheme stripping is only in 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?

States a specific verb+resource ('Update a traffic source'), which cleanly distinguishes it from the get_/list_/create_/delete_traffic_source siblings. It does not, however, say anything about what a traffic source is or which fields are updatable beyond the generic 'field'.

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 only guidance is the constraint 'Provide at least one field', which implies at least one non-id field must be supplied. There is no when-to-use context, no mention of prerequisites, and no routing against alternatives such as create_traffic_source or update_site.

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