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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world, so the safety profile is covered. The description adds two things annotations cannot: the required `inbox:read` scope and a prompt-injection warning that user-written text appears in untrusted_fields and must never be treated as instructions. That is substantive behavioral context for an agent consuming the output.

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 tight sentences with the capability stated first and the permission/security caveats after. Nothing is padding, though the untrusted_fields sentence is dense enough that its intent could be split more cleanly.

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 read-only list tool with no output schema, the description covers auth and output-safety concerns well. It leaves the meaningful operational gaps — how pagination works (limit/cursor) and what channel values are accepted — unaddressed, which matters because the schema provides no descriptions.

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% for all four parameters. The description only alludes to search (q) and unread counts; limit, cursor, and channel are left entirely undefined, so pagination and channel filtering must be guessed. It does not 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 with scope ('List my conversations') plus the value-adds ('unread counts and search'), so the operation is immediately identifiable. It does not differentiate from nearby siblings such as get_conversation, list_messages, or the generic search tool, so an agent must infer the boundary.

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?

There is no explicit when-to-use or when-not-to-use guidance and no named alternative. The mention of 'search' hints that a query is possible, but the description never says to prefer this over list_messages or search when looking for specific content.

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