Create outbound fax

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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=false, and openWorldHint=true, so the safety profile is covered. The description adds nothing beyond "(POST /faxes)": it does not say whether the fax is dispatched immediately, whether a file must be uploaded/base64-encoded, what account/permission is required, or whether retries could send duplicate faxes (important given idempotentHint=false).

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 fragments with no filler and the purpose front-loaded. Size is appropriate; the parenthetical endpoint is near-zero value for an agent but not enough bloat to penalize further.

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?

This is an outward-facing, non-idempotent mutation with 6 parameters and no output schema, so the description carries real burden. It omits what is returned (fax id/status), any send semantics, file encoding expectations, and error cases — an agent could construct the call but not predict its effects.

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 schema is nominally the source of truth and the baseline is 3. However, the schema descriptions are pure tautologies ("Body field file (required)") and the tool description offers no compensating detail such as accepted file formats or the meaning of `header`, so it does not improve on structured data.

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 pairs a specific verb and resource ("Create outbound fax") and the tool name/sibling set (list_faxes, get_fax, delete_fax) makes the create role unmistakable. It stops short of naming a sibling or stating scope (e.g. vs. send_sms or initiate_call), so it is clear but not fully differentiated.

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 choose this over neighbors like placetel_send_sms, placetel_list_faxes, or placetel_initiate_call, and no prerequisites or exclusions. The only content is the HTTP verb/path, which does not help an agent decide.

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