update_attachment

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

With no annotations available, the description carries the burden of behavioral disclosure and does so reasonably well. It explicitly notes the 'empty = leave alone' semantics for file_name and description, and warns that older Redmine versions return 404. It stops short of discussing permissions, response format, or side effects, but the disclosed traits are meaningful and non-obvious.

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 compact and well-structured. The first sentence states the core action, the second provides a compatibility caveat, and the Args block lists parameters clearly. Every sentence earns its place; there is no redundant or vague language.

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 presence of an output schema, the description does not need to explain return values. It covers all parameters, explains the non-obvious empty-string behavior, and notes a version-specific error case. This is sufficient for an agent to correctly invoke the tool and understand when it will fail.

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 0%, so the description must compensate. The Args section explains the purpose of each parameter, with the 'empty = leave alone' clarifications for file_name and description adding significant semantic value beyond the raw schema. attachment_id receives only minimal explanation, but it is required and self-explanatory.

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 clearly states an action ('Rename an attachment or change its description') on a specific resource ('attachment'), and adds a distinctive qualifier ('without re-uploading it') that differentiates it from delete-and-recreate workflows. It stands apart from sibling tools like get_attachment and delete_attachment by focusing on the update operation.

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 phrase 'without re-uploading it' implicitly signals when to choose this tool over the alternative of deleting and re-attaching a file. It gives clear context for the intended use case, though it does not explicitly name sibling tools or provide negative exclusions, which keeps it a step below a 5.

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