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

Annotations already declare readOnly/idempotent/non-destructive, so the description's value is in the extras it supplies: returned timezone and effective quota, the null-means-unlimited convention, the durable id+revision handle needed for follow-up mutations, and the operational meaning of the "uncertain" state. Remaining gaps are ordering/pagination rather than safety or side effects.

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?

Front-loaded with purpose and generally dense, but the quota sentence ("limit=null and remaining=null mean a personal unlimited scheduling allowance") introduces terms (Transports, Telepath, quota) that are never grounded and collide with the identically named input parameter, costing clarity per word.

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, the description does a fair job sketching the return surface (delivery states, timezone, quota, id/revision) and the exclusion of Telegram-native scheduled messages. It still omits default page size, ordering, and whether cancellation of a delivered message is possible, which matters for a list-then-mutate workflow.

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%, so the description must carry the parameter burden. It explains the status values "scheduled" and "uncertain," but leaves the limit parameter (1-100) completely undefined and the "limit=null and remaining=null" sentence is ambiguous — it reads as a quota field in the response, not the integer input parameter, which risks misreading.

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 ("List Telepath scheduled messages and delivery states for this account") and explicitly delimits scope with "This list does not include messages scheduled independently in Telegram," which cleanly separates it from the sibling schedule_message/cancel_scheduled_message operations. An agent can identify the tool without opening the schema.

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?

Gives concrete usage conditions: "Filter status=scheduled for pending messages," "Pending messages can be changed or cancelled using id and revision," and "Uncertain means inspect the destination before any new send." It does not name the sibling tool to use for editing/cancelling, so the routing is implied rather than explicit.

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