mark_read

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

Annotations already include idempotentHint=true, readOnlyHint=false, destructiveHint=false, and openWorldHint=true. The description adds value by disclosing reversibility, immediate execution without approval, audit logging, and no other side effects. No contradiction.

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, clearly structured, with every sentence earning its place. The most important facts (what it does, reversibility, side effects) are front-loaded.

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 simple mark-as-read tool with full schema coverage and no output schema, the description is complete. It tells the agent what happens, what doesn't happen, and what to expect.

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 already documents all four parameters well. The description adds a slight behavioral note about execution, but doesn't need to add parameter-level detail because the schema already covers 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 ('mark'), resource ('a message'), and the two possible states (read/unread). The description clearly distinguishes it from siblings like move_message, delete_message, and send_mail.

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 explains the operation is reversible and immediate, and mentions the audit log. It doesn't explicitly state when to use this vs reading a message, but the purpose is clear enough for an agent to infer context.

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