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

The description adds valuable behavior beyond the annotations: it discloses the lazy-creation side effect on first read ('Lazy-creates the note on first read if absent'), explains why the endpoint always returns a note, and states the authorization model. This is especially useful given readOnlyHint is false and idempotentHint is true—the description coherently explains both annotation signals.

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?

Two tight sentences deliver the core purpose, the lazy-creation behavior, and the authorization model with no filler. The most important differentiator (fetch vs. note type) is front-loaded.

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 getter with an output schema, the description covers everything an agent needs to invoke it correctly: what it returns, side effects, auth requirements, and required parameters. The presence of an output schema means return-shape details need not be repeated in the description.

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%: both characterId and documentType have clear descriptions, including the 'NOT the vault character id' warning and the dm-notes/player-notes enum semantics. The description adds no parameter-level detail beyond the schema, which is acceptable given the schema already carries the heavy lifting.

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 opens with a specific verb ('Fetch') and a precise resource ('DM-side or player-side note attached to a play character'), distinguishing the read operation from the related sibling play_update_character_note. It also clarifies the two note variants, leaving no ambiguity about what is retrieved.

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 this is the read path for character notes and even notes the authorization context ('campaign permission'), but it does not explicitly state when to prefer it over alternatives or when not to use it. There is no direct referral to play_update_character_note for modifying notes, so usage guidance 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.