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

The readOnlyHint annotation already establishes that this is a safe read operation. The description adds 'in full,' which signals that the complete passage is returned without truncation, but it does not discuss error behavior, permissions, or response size limits.

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, front-loaded sentence with no filler. Every word contributes to identifying the resource, the lookup key, and the completeness of the result.

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 simple read-by-id tool with an annotation covering safety and no output schema, the description is roughly adequate but leaves gaps: it does not clarify the id format or what happens when a passage is not found. It is the minimum viable level for correct invocation.

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% and the single 'id' parameter has no schema description. The description only says 'by its id,' which barely restates the schema and does not specify the expected format, source, or constraints of the id.

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 resource ('library passage'), the lookup key ('by its id'), and the retrieval scope ('in full'). It does not explicitly distinguish itself from sibling tools like search_library, so it falls short of a 5.

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 implies the tool is used when an id is known, but it gives no guidance on when to use it versus search_library or other siblings, nor any exclusions or alternatives. There is no explicit when-to-use instruction.

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