mark_as_read

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It mentions the single-account constraint and account requirement, but does not disclose effects on message state, error handling, return values, or idempotency. For a mutation tool, this is insufficient.

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 sentence that is direct and front-loaded with the action. It contains no filler or redundant information, making it highly concise.

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 the tool mutates messages and lacks both annotations and an output schema, the description should provide more context about the operation's effects and expected outcome. It covers the account constraint but leaves out crucial details like return behavior or what happens after marking messages as read.

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 the schema already documents both parameters. The description adds only 'account required', which reinforces the required field but adds no extra meaning for message_ids. Baseline of 3 is appropriate.

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 marks messages as read, uses a specific verb ('Mark'), and specifies the resource ('messages as read'). It also adds scope ('in one account') and a prerequisite ('account required'), which distinguishes it from sibling tools like archive_emails or read_emails.

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 phrase 'account required' and 'in one account' provide usage context by indicating a prerequisite and a limitation. However, it does not explicitly mention when to use this tool versus alternatives, nor does it provide exclusions or comparisons to sibling tools.

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