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

Annotations already declare readOnly/idempotent/openWorld, but the description adds real behavioral context: indexed text is returned when available, otherwise extraction happens on the fly without persisting, and unsupported types (PDF, PowerPoint, images) yield empty text with an explanatory note. This caching/persistence nuance is not derivable from the annotations.

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?

Two dense sentences, front-loaded with the primary outcome and followed by the fallback and failure behavior. Every clause carries information an agent needs.

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 one-parameter read tool with no output schema, the description covers input identification, return content, the extraction fallback, unsupported-type behavior, and the escalation path to indexing. Nothing essential to correct invocation is missing.

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% for the single code_or_id parameter, so the schema already documents its type and meaning. The description only restates the accepted formats (REF code, id), adding no syntax or edge-case detail beyond the schema.

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?

States a specific verb and resource ('Return the extracted plain text of a Reference Library item') plus the identifier forms accepted. It is clearly separable from sibling tools like traceable_library_search, traceable_library_index, and traceable_library_add_reference.

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?

Gives a clear use condition (retrieve text by REF code/id) and routes to traceable_library_index for persisting supported text for search. It does not explicitly state when NOT to use this versus traceable_library_search, so it falls short of full when/when-not coverage.

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