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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false, and destructiveHint=false; the description adds only scope context ('every registered' and the registry-vs-prose distinction). It does not describe response shape, pagination, or invalid-type behavior, but those gaps are less critical given the annotation coverage.

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 two sentences with the main action front-loaded and the supplementary scope note in the second sentence. Every phrase adds value, including the example types and registry limitation.

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 single-parameter, read-only listing tool with complete schema coverage and rich annotations, the description covers what the tool returns, its scope boundary, and typical input values. No output schema exists, but the simple list operation does not require a more detailed contract.

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 schema only says the type is 'The canon @type to filter on,' while the tool description enriches it by listing valid examples (DoctrineDoc, Wall, RingCommitment, Pattern, Promise) and framing the parameter as a filter over registered entries. This goes beyond the schema's basic type definition.

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 states 'List every registered canon entry of a given @type' with concrete example types, clearly identifying the action, resource, and scope. The title and examples differentiate it from siblings like list_types and lookup by focusing on filtering entries by type.

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 establishes the appropriate use case: retrieve all canon entries of a specified type, and cautions that the prose corpus is broader than this registry. It does not explicitly name alternatives or exclusion conditions, but the context is clear enough for an agent to select this over broader search tools.

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