get-fileDownload a sent or received fax file.
Side effects: none (read-only); returns base64 file bytes in structured output.
| Name | Required | Description | Default |
|---|---|---|---|
| fax_id | Yes | Fax record ID whose file should be downloaded. | |
| format | No | 'pdf' (default) or 'tiff'. | |
| user_id | No | Fax.Plus user ID. Default: self. |
| Name | Required | Description | Default |
|---|---|---|---|
| data_base64 | Yes | ||
| content_type | Yes |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The annotations already signal read-only/idempotent behavior, and the description adds a useful behavioral trait by stating the result is base64 file bytes in structured output. This is consistent with the annotations, so no contradiction exists.
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 short and front-loaded with the purpose. The 'Side effects: none (read-only)' clause largely duplicates the readOnlyHint annotation, so not every sentence adds unique value, preventing a 5.
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 the annotations, full schema coverage, and output schema, an agent has enough to invoke this tool correctly. It lacks explicit sibling differentiation and usage alternatives, which keeps it from being fully complete.
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 each parameter already has a meaningful description. The tool description itself adds no additional parameter-level semantics, so the baseline score of 3 is appropriate.
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 clear action ('Download') on a specific resource ('sent or received fax file'), which conveys the tool's primary purpose. However, it does not explicitly distinguish this from sibling download/preview tools like get-file-page or get-fax-thumbnail, so it falls just short of a 5.
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 tool instead of related file-retrieval tools, nor any exclusions or prerequisites. The phrase 'sent or received' describes scope but does not give the agent decision criteria among the large sibling set.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.