Mark chat as read

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

Discloses important traits beyond annotations: idempotent (safe to repeat), no notification to other party, does not modify/delete messages. Annotations (idempotentHint: false, destructiveHint: false) are partially contradicted by the idempotency claim, but the description adds value. Not full 5 due to 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?

Three sentences, front-loaded with the primary action. Each sentence serves a purpose: main action, side effects, idempotency guarantee. No 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?

Complete for a simple mutation tool without output schema. Explains what happens (read receipt, clear counter), idempotency, prerequisites. No missing critical information.

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% with detailed descriptions for all 4 parameters. The tool description adds only the origin of chat_id (from messenger_get_chats_v2). Baseline 3 is appropriate as description adds marginal value beyond 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?

Description clearly states the action: 'Marks the unread messages of the specified chat as read'. It specifies verb (mark as read), resource (unread messages of chat), and outcome (recording read receipt, clearing unread counter). Distinguishes from sibling tools like messenger_get_chats_v2 (list) or messenger_delete_message (delete).

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?

Provides context: 'Requires chat_id (from messenger_get_chats_v2)' and explains behavior ('Sends NOTHING to the other party'). Lacks explicit when-not-to-use or alternatives, but the context is clear enough for selection among siblings.

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