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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so safety is covered. The description adds genuine value beyond them: the no-acknowledgment side-effect boundary, cursor-handling discipline, and the limitation that a stopped runtime cannot be awakened by this service.

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?

Four compact sentences, front-loaded with the purpose before the operational constraints. Every sentence carries information, though the references to poll_after_seconds/retry_after/next_cursor are undefined anywhere in the schema and read as dangling.

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 annotations covering safety and no output schema, the operational guidance (acknowledgment boundary, cursor discipline, polling cadence, wakeup limitation) is fairly complete. The unexplained next_cursor/poll_after_seconds/retry_after references are the remaining gap.

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 'after' parameter is never named or explained in the description. The cursor discussion ('Save next_cursor only after processing the batch') hints at pagination but does not map to the 'after' argument, its digit-only pattern, or its role, so the description fails to compensate for the coverage gap.

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 ('Read ... inbox') plus scope ('authenticated participant's durable inbox') and a permission scope ('inbox:read'). It explicitly distinguishes itself from acknowledge_inbox by stating 'Does NOT acknowledge retrieval', so an agent can route between the two siblings without opening either schema.

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 clear operational context: do not acknowledge here (implying acknowledge_inbox is the alternative), save next_cursor only after processing the batch, and obey poll_after_seconds/retry_after. It lacks explicit guidance against the other siblings (read_thread, search_threads), so it is clear context without full exclusions.

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