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

Annotations already declare destructiveHint=true, idempotentHint=true, and readOnlyHint=false, so the safety profile is covered structurally. The description adds the reversal relationship to messages_bot and a caution against proactive use, but does not describe what state changes or what happens to non-matching IDs. Modest added value over annotations.

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?

A single front-loaded sentence stating the action, scope, and sibling relationship, plus one short usage constraint. No filler; every clause earns its place.

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 two-required-parameter mutation tool with full schema coverage and a rich annotation set, the description supplies the essential safety guidance (only on explicit user request). It is nearly complete; return behavior is not described, but no output schema exists and the sibling messages_bot covers the mirror operation.

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 100%: logId is defined as a Guid and messageIds documents the 1-500 range. The description only echoes 'by ID' and 'one or more', adding no meaning beyond the schema, so the baseline 3 applies.

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 ('unmark') and resource ('log messages as bot-generated'), and explicitly differentiates itself from the sibling messages_bot by calling itself 'the opposite of messages_bot.' An agent can distinguish it from all siblings without opening a 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?

Adds an explicit gating condition: 'Only call this when the user has explicitly asked to undo a bot marking.' This tells the agent when to use it, and the sibling reference points to the reverse operation. It stops short of enumerating alternatives or exclusions beyond that one rule.

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