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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the agent knows it's a safe, read-only operation. The description goes beyond annotations by clarifying that it reads the live collaborative document rather than the cache, and explains the 502 error behavior and permission levels (viewers can read, editors can replace). These are useful behavioral details not captured by annotations.

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 succinct and front-loaded with the core purpose and usage context. Every sentence adds value: the first states the action and ETag, the second explains the live read and the ETag's role, the third gives error handling and permissions. No wasted words.

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?

Given the tool's simplicity (one parameter) and the presence of an output schema (which likely describes the response structure), the description covers all necessary operational details: what it returns (body + etag), how to use the etag, error handling, and permission model. Nothing critical is missing.

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?

The schema already documents the id parameter with 100% coverage, so the description adds no new parameter-specific meaning. The baseline for high coverage is 3, and the description doesn't enhance the parameter beyond what's in the schema.

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?

Tautological: description restates name/title.

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?

Explicitly states when to use: 'immediately before rewriting a canvas' to guard against concurrent edits. It also tells the agent to pass the etag as If-Match on the update tool, and mentions the 502 retry behavior. This provides clear operational guidance.

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