Read attachment / screenshot

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

Annotations already declare readOnlyHint=true and destructiveHint=false, but the description adds meaningful behavior: authentication requirement, conditional return formats (images as viewable, text as text, else base64). This goes beyond the annotations and helps the agent anticipate the response shape.

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?

Three sentences, front-loaded with the primary action, followed by return format details and a clear usage hint. No fluff or redundant content.

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 no output schema, the description does well to explain return types and the tool's role. It covers authentication, format handling, and typical use cases. It could mention error behavior or size limits, but for this simple read operation the core context is present.

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 coverage is 100% and both parameters have descriptions. The tool description adds value by explaining the url parameter accepts both full and relative forms, and project_id has a fallback to GITLAB_PROJECT_ID, which enriches the schema's static field definitions.

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 uses a specific verb ('Downloads') and identifies the resource ('an attached file from GitLab'). It clearly distinguishes from sibling tools like gitlab_get_file by stating 'This is how you look at screenshots pasted into issues, merge requests and comments' and describing the output formats.

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 description provides clear context for when to use it: viewing screenshots/attachments from issues, merge requests, and comments. It implicitly distinguishes from repository file tools but does not explicitly exclude alternates like gitlab_download_url or gitlab_get_file.

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