Configure a number as a fax number

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

Annotations already declare the operation is a non-read-only, idempotent, non-destructive, open-world mutation. The description adds nothing beyond that profile: it does not say whether existing fax settings are replaced by the PUT, what happens to unlisted fields, or what permissions are required. It essentially restates the title.

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, action front-loaded with the endpoint path as secondary detail. Nothing is wasted, though the path adds little decision value for an agent.

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 9 parameters, 3 required, no output schema, and a mutation of telephony settings, the description should explain at minimum what faxpin and faxheader represent and the effect of the call. Those required-but-opaque parameters are left entirely undocumented, so an agent cannot call this reliably without guessing.

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 mentions number_or_id via the endpoint path but adds no meaning for faxpin, faxheader, faxsettings, or faxwhitelist beyond the schema's placeholder 'Body field X' labels, so it does not compensate for the schema's semantic thinness.

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 states a specific verb and resource: configuring a number as a fax number, plus the underlying endpoint. It is distinguishable from the read sibling (get_webex_number_fax_settings) and delete sibling, but it never names them, so the differentiation is inferred rather than stated.

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?

There is no guidance on when to use this versus get_webex_number_fax_settings or remove_webex_number_fax_settings, nor any prerequisites (e.g. number must be a Webex-enabled number). The agent must infer selection purely from the verb.

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