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

Annotations only declare readOnlyHint=false and destructiveHint=true; the description goes well beyond them with the auth requirement, the fact that link and delivery mode are immutable across updates, the advisory deliveryModeReason field, and a specific error code for legacy read-only pages. It stops short of stating that prior content is overwritten, which is the main destructive consequence an agent should know.

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, auth, and return value before the conditional invariants and error case, and every sentence carries information. The delivery-notice sentence is a dense run-on that could be split, keeping it short of perfect.

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 five-parameter mutation tool with no output schema, the description covers auth, mutation semantics, immutable attributes, the return payload, and the legacy read-only failure mode with a remediation path. An agent has everything needed to call it correctly and to interpret a 409.

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 100%, so every parameter including the long format enum list is already documented in structured data. The description adds only indirect hints (new content, unchanged delivery mode) and no format or ID semantics beyond the schema; baseline 3 applies.

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 ('Update an existing BrewPage HTML/Markdown page') plus the return value, which separates it from the publish_* siblings that create new pages. It never names those siblings explicitly, so the differentiation is inferred from the word 'existing' rather than stated.

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 a clear precondition (owner token required) and an explicit when-not case: publications older than 5 October 2026 are read-only and return 409 OLD_PUBLICATION_READ_ONLY with a createUrl to publish anew, which routes the agent to the correct alternative. It does not say when to prefer update_json or get_page, but the core usage boundaries are covered.

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