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

Annotations already declare destructiveHint=true and idempotentHint=false, and the description adds value beyond that: the reversibility window is time-bounded by the friend's read status, and 'A document sent with the note is taken back with it' discloses a cascading side effect the annotations cannot express. It does not contradict the destructive/non-idempotent profile.

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?

Four compact sentences, front-loaded with purpose and then the precondition, with the parameter guidance last. Every sentence carries information; minor overlap between the usage condition and the read-status warning keeps it from being maximally tight.

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?

No output schema exists and both parameters are fully documented in the schema, so the description's responsibilities are purpose, preconditions, side effects, and parameter sourcing — all of which are covered. An agent has everything needed to invoke it correctly.

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 baseline is 3, but the description goes further by naming the provenance of id (leave_note, or your_unread_notes in check_notes) and clarifying the 'or' relationship between id and to ('most recent unread note to them'), which the schema only partially conveys.

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 states a specific verb and resource ('Take back a note your person sent') plus the decisive scope condition ('while the friend hasn't read it yet'), which cleanly separates it from leave_note, check_notes, and report_note in the sibling list.

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?

It gives an explicit triggering condition ('Only when your person asks') and an explicit negative condition ('Once the friend has read it, it can't be unsent'), plus routing to sibling tools (leave_note, check_notes) as the sources of the id. Both when-to-use and when-it-will-fail are stated.

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