mark_message

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It states the tool modifies flags, implying mutation, but doesn't cover critical aspects like required permissions, side effects (e.g., if changes are reversible), error handling, or response format. The examples ('read/unread', 'flag/unflag') add some context but are insufficient for a mutation tool with zero annotation coverage.

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?

The description is a single, efficient sentence that front-loads the core purpose with clarifying examples. Every word earns its place, avoiding redundancy or fluff, making it easy to parse quickly.

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?

Given this is a mutation tool with no annotations and no output schema, the description is incomplete. It lacks details on behavioral traits (e.g., permissions, side effects), output values, and usage guidelines, which are critical for an agent to invoke it correctly. The high schema coverage helps with parameters, but overall context is inadequate.

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%, so the schema fully documents all four parameters. The description adds minimal value beyond the schema by hinting at flag examples ('\\Seen', '\\Flagged') and the tool's purpose, but it doesn't explain parameter interactions (e.g., how 'action' affects 'flags') or provide usage semantics. Baseline 3 is appropriate as the schema does the heavy lifting.

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?

The description clearly states the tool's purpose with a specific verb ('Set or remove') and resource ('flags on a message'), including examples ('mark as read/unread, flag/unflag'). It distinguishes from siblings like 'delete_message' or 'move_message' by focusing on flag manipulation rather than deletion or relocation, though it doesn't explicitly differentiate from all siblings.

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?

The description provides no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., needing a message UID), exclusions, or comparisons with sibling tools like 'get_message' for viewing flags or 'search_messages' for finding flagged messages, leaving usage context implied at best.

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