epost_set_read_status

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

No annotations provided, so the description carries full burden. It states the tool marks letters read/unread, implying state change, but does not disclose side effects, required permissions, rate limits, or behavior for non-existent letters.

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?

Single sentence of 5 words, highly concise and front-loaded. Lacks structured details but achieves brevity without wasted words.

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?

With no output schema, no annotations, and 2 parameters, the description is too minimal. It does not explain return behavior, error conditions, or what happens on success/failure. Incomplete for a mutation tool.

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 0%. The description adds no meaning beyond the schema: 'by id' is redundant with the 'letter_ids' parameter. The 'status' parameter is only defined by its enum values in the schema.

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 'Mark letters READ or UNREAD by id.' clearly states the action (mark), the resource (letters), and the specific states (READ/UNREAD). It distinguishes this tool from siblings like epost_unread_count (count only) and epost_status (likely different).

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?

No usage guidelines provided. The description does not indicate when to use this tool versus alternatives, nor does it mention prerequisites (e.g., login required) or context for setting read vs unread status.

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