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

The description goes well beyond the annotations by explaining PUT semantics (full replacement), the contribute-permission authorization model, notification side effects, and the OUT_OF_SYNC failure mode with 'nothing is written.' This gives an agent a precise model of what happens before invoking the tool.

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?

The description is dense but every sentence earns its place: purpose, replacement semantics, authorization, notification behavior, and concurrency requirement. The most critical requirement (baseUpdatedAt) is emphasized with caps and placed last for salience.

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?

The description covers most operational context: authorization, notifications, concurrency, and failure behavior. The only notable gap is that it does not explicitly identify how the target note is selected (e.g., a note ID or DM/player side flag), though the reference to 'the same note' from play_get_character_note implies it.

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?

Even though the input schema is empty, the description documents the two meaningful parameters: `description` (replaces the body) and `baseUpdatedAt` (must be a fresh copied timestamp or the call fails with OUT_OF_SYNC). This fully compensates for the sparse schema and is essential for correct invocation.

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 uses a specific verb ('Update') and resource ('DM-side or player-side note attached to a play character'), making the tool's scope immediately clear. It also distinguishes this from sibling tools like play_get_character_note by focusing on mutation rather than retrieval.

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 gives strong usage context: it requires the caller to first read the note via play_get_character_note and copy updatedAt into baseUpdatedAt, and it explains the authorization path. However, it does not explicitly name alternative tools or state when NOT to use this tool, so it stops short of full exclusion guidance.

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