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

Annotations already declare read-only, idempotent, and non-destructive behavior. The description adds valuable context beyond that: it notes the tool is keyless, that download URLs are constructed rather than directly served, and clarifies the scope as archive.org items, not Wayback snapshots. This gives the agent a better understanding of what to expect.

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 exceptionally concise: two sentences plus a parenthetical. It front-loads the core action and resource, then provides essential usage hints and a scope clarification. Every statement earns its place without unnecessary detail.

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?

The tool is simple, and the description covers the action, input, output fields, prerequisites, and limitations. The schema covers parameters and defaults, so nothing critical is missing. No output schema exists, but the description sufficiently explains what the tool returns.

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%, with both 'id' and 'limit' fully described in the input schema, so the baseline is 3. The description reinforces the 'id' parameter but does not add additional meaning beyond the schema for 'limit' or return behavior. It neither enhances nor detracts from the schema's clarity.

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 ('List') and clearly identifies the resource: downloadable files for an archive.org item by identifier. It also lists the return fields (name, format, size, constructed download_url) and explicitly distinguishes from Wayback snapshots, setting it apart from sibling tools like wayback_check.

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 gives explicit when-to-use guidance: 'Use search / get_metadata first to find an identifier.' It also states what it is not for ('not Wayback snapshots') and that it is keyless, indicating no authentication setup is needed. This is clear and actionable.

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