update_entry

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

With only readOnlyHint=false and destructiveHint=false, the description adds meaningful behavioral context: partial updates only, unchanged fields preserved, and entry type immutable. The schema adds even more behavioral nuance (subject no-op on notes, updatedAt semantics, last-attachment rejection), but that lives in structured fields rather than the main description.

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?

Three tight sentences: the action and resource, the update semantics, and the intended use. No filler, and the most important constraints are 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 mutation tool with no output schema, the definition plus schema conveys the required id, updatable fields, partial-update behavior, and attachment-removal constraints. It does not describe the return value or auth scopes, but the parameter and behavior coverage is strong enough for an agent to call 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 description coverage is 100%, so the baseline is 3 and the schema already documents id, content, subject, and removeAttachmentIds well. The tool description lists content/subject as updatable fields and states the partial-update rule, but it adds little over the already-rich parameter descriptions.

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 operation (edit an existing timeline entry) with the affected resource and scope (fields content, subject, attachment removals). It distinguishes itself from add_note/create/delete siblings by framing it as correcting or extending a previously added note. The 'cannot change the entry's type' note removes ambiguity about type-changing behavior.

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 use context: 'Use this to correct or extend a note added previously.' It states limitations (cannot change type) and, via the schema's removeAttachmentIds note, points to upload_attachment for adding attachments. There are no explicit exclusions naming alternatives like add_note or delete_entry, so it stops short of a fully explicit when-not guidance.

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