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

Annotations already declare idempotentHint=true and destructiveHint=false, so the bar is lower. The description nonetheless adds genuinely useful context: the read state change applies retroactively to all earlier messages, it targets the newest message by default, and 'Nothing is sent' disambiguates it from sibling messaging tools. It stops short of noting any rate limits or permission requirements.

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 short sentences, front-loaded with the effect and followed by the default behavior and the negative guarantee. No filler.

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 two-parameter, non-destructive state tool with full schema coverage and no output schema, the description covers effect, scope, and default adequately. Only minor gaps remain (permissions, error behavior on an unknown chat_id).

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 both parameters are already documented in the schema. The description restates the message_id default ('Defaults to the newest message') but adds no format or edge-case detail beyond the schema, so the baseline 3 applies.

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 and resource ('clear the unread badge on a conversation by marking ... as read') and precisely defines the scope ('a message, and everything before it'). This distinguishes it cleanly from sibling write tools like telegram_send_message and telegram_edit_message.

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 implies its use case (clearing unread state) but never states when to prefer it over alternatives or any prerequisites such as needing a resolved chat_id. Usage is inferable but not spelled out.

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