List User Messages

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

Annotations already declare readOnlyHint=true and destructiveHint=false, but the description adds significant behavioral context: lists both unread/read, active/archived depending on server defaults, pagination details, error handling (authentication failed, permission denied). A minor deduction for including a somewhat tangential note about JSON structuredContent and cache metadata, which may confuse rather than clarify.

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 well-structured with clear sections (Args, Returns, Examples, Pagination, Error Handling) and front-loaded purpose. However, it includes a somewhat generic paragraph about JSON structuredContent and cascade_read that is not directly relevant to this tool, slightly reducing conciseness.

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?

Despite no output schema, the description thoroughly documents the return format (including fields like total, count, offset, has_more, next_offset, messages array with subfields) and error responses. Pagination and error handling are fully explained, making it complete for a list tool with two optional parameters.

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% with good descriptions for limit and offset. The description adds value by explaining pagination usage (e.g., 'Use with limit + has_more to iterate') and providing default values and ranges beyond the schema. This extra context justifies a 4 rather than a baseline 3.

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 it lists in-Cascade mailbox messages for the authenticated user, with specific verb 'list' and resource 'messages'. It distinguishes from siblings by noting that message IDs can be used with cascade_mark_message or cascade_delete_message, and gives explicit examples of when not to use this tool (e.g., for asset subscribers use cascade_list_subscribers).

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 explicit guidance on when to use (e.g., 'What's in my Cascade inbox?') and when not to use (e.g., 'Don't use when: You want an asset's relationships or subscribers — use cascade_list_subscribers'). It also gives alternatives and a clear example for checking workflow messages.

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