Download Redmine Attachment

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

Beyond the readOnly/idempotent/destructive annotations, the description discloses substantial runtime behavior: bytes are either returned as an image or saved to disk, saved files land in /tmp/redmine-mcp and are configurable via REDMINE_DOWNLOAD_DIR, and there are explicit size limits (10.0 MB saved files, 4.0 MB inline images). No annotation is contradicted.

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 front-loaded with the core behavior, uses a compact bulleted Args section for the two parameters, and closes with the two most important operational constraints (save location and size caps). Every sentence contributes information an agent needs.

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 two-parameter tool with no output schema, the description covers the input source, mode semantics, return behavior (details plus either image or saved path), file location, configuration, and limits. Nothing needed for a correct call is left unstated.

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?

Even though the schema covers both parameters, the description adds real meaning: attachment_id is sourced from redmine_get_issue with a specific include argument, and mode is explained with concrete auto/image/file outcomes rather than just 'How to return the bytes'. This materially improves correct invocation.

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 opens with a clear verb-resource pair ('Download a Redmine attachment by ID') and immediately clarifies the mode-dependent outcome, so an agent can tell it from related tools such as redmine_upload_attachment or redmine_get_issue without opening schemas. It is specific and well 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?

It explicitly tells the agent where to obtain attachment IDs (redmine_get_issue with include='attachments') and defines exactly when to choose auto, image, or file mode. Although there is no alternate download tool to contrast with, it gives concrete selection criteria and behavioral expectations.

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