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

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is covered. The description adds genuinely new behavioral context not in annotations: the effect is state-changing but auto-reversible on the next inbound message, which materially affects whether an agent should hesitate. It stops short of saying what happens when closing an already-closed conversation or what errors to expect.

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?

One line, front-loaded with the operation class (WRITE) followed by action, effect, and endpoint. Every clause earns its place and nothing is padded.

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 mutation with no output schema, the definition covers what changes, the reversibility trait, and the transport. Minor gaps remain on error/idempotent-replay behavior and on the accountId path variable that the schema does not expose, but nothing blocks correct invocation.

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?

There is a single required parameter with 100% schema description coverage, so the schema already carries the semantics and baseline 3 applies. The description mentions the conversationId path segment but adds no format, encoding, or lookup guidance beyond it.

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 ('mark a conversation closed in the Sakari inbox') with a leading WRITE marker, which cleanly separates it from read-only siblings like sakari_get_conversation and sakari_list_conversations. The endpoint path reinforces exactly what object is mutated.

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?

Usage is only implied by the parenthetical that a new inbound message reopens the conversation, which hints the close is not permanent. There is no explicit statement of when to close versus when to leave a conversation open, and no named alternative (there is no reopen sibling to route to).

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