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

Annotations already declare readOnlyHint and openWorldHint=false, and the description confirms 'Read-only; takes no input'. It adds value beyond the annotations by disclosing the receipt format (pauhu-library-receipt/2), the fact that every code_* answer carries one, and the fields each catalogue entry exposes. It does not describe ordering or pagination, but for a static read-only listing this is solid.

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 compact sentences that front-load the catalogue contents before the receipt/verification aside. Nothing is redundant, though the phrase 'what the code tools answer' costs a beat of clarity for no real gain.

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?

With no output schema, the description carries the burden of describing the return payload, and it does list the entry fields (id@version, tool, input). Combined with the receipt explanation and the zero-parameter, read-only nature of the tool, an agent has what it needs, though the exact entry structure remains loosely specified.

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?

The tool takes no parameters, so the baseline is 4; the description's 'takes no input' simply confirms the empty schema rather than adding semantics, which is appropriate here.

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 concrete resource (the catalogue of code_* tools) and enumerates what each entry contains – id@version, the tool to call, and its input. The opening clause 'what the code tools answer' is slightly indirect, but the following sentence disambiguates it and separates it from library_verify, which it names explicitly.

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 workflow context: every code_* answer carries a receipt, and library_verify is the tool that checks issuance and integrity. That is enough for an agent to know the catalogue is the discovery step and library_verify the verification step, though it never frames an explicit 'use this when' condition or exclusion.

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