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

Annotations already declare destructiveHint=true, readOnlyHint=false, and idempotentHint=true, so the safety profile is covered. The description adds real value beyond that by framing the operation as the inverse of messages_fix and warning against speculative invocation. It does not describe what state changes on reopen or the blast radius of a rollback.

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 sentences, no filler, with the action and the anti-speculation guard both front-loaded. Every clause carries information an agent needs.

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?

A three-parameter mutation tool with no output schema, but annotations carry the safety profile and the schema fully documents the parameters. The description covers purpose and invocation discipline; only the post-reopen state effect is left implicit.

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%, so logId, messageId, and markAllAsOpen (including the grouping-hash semantics) are already documented in the schema. The description adds no parameter-level meaning, which is acceptable but earns only the baseline.

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?

Specific verb ('Reopen') plus resource ('a fixed log message by ID'), and it explicitly positions itself as the inverse of the sibling messages_fix. An agent can distinguish it from messages_fix, messages_hide, and messages_unhide without opening any 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 an explicit when-to-use condition ('Only call this when the user has explicitly asked to reopen this message') and an explicit when-not ('never speculatively while just investigating errors'). This is the strongest form of routing guidance.

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