Browse an OPDS catalog

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

With no annotations, the description is the sole source of behavioral info. It explains the output structure (navigation links, entries with links) and the input format (URL, auth). However, it does not disclose error behavior, pagination, rate limits, or side effects. The description adds marginal value beyond what the input schema already conveys.

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 a single sentence that efficiently conveys the core functionality and output. However, it is somewhat long and could be split for readability. It is not overly verbose, so it earns a 4.

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 complexity of the tool (no output schema, no annotations, moderate parameter count), the description covers the return values but lacks details on error handling, pagination limits, or authentication failure scenarios. It is sufficient for basic understanding but not 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%, so the description does not need to add parameter details. However, it adds no additional context beyond the schema (e.g., clarifying when url is required). The baseline of 3 is appropriate since the schema already explains all three parameters.

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 the tool fetches an OPDS catalog document and returns navigation links and entries. It specifies the document types and formats, aligning well with the title. However, it does not explicitly differentiate from sibling tools like opds_search or opds_download, though the purpose is distinct enough given the context.

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 no guidance on when to use this tool versus alternatives, nor does it mention prerequisites, authentication requirements beyond the schema, or scenarios where it should not be used. This lack of usage direction is a significant gap.

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