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

Annotations already cover readOnly/openWorld/non-destructive, but the description adds real value beyond them: the canvas-online prerequisite, the sensitivity warning that previewURL must stay private, and the recommended screenshot_draft-before-publish_draft ordering. These are behavioral traits not derivable from the structured fields.

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 dense sentences with the core action and returned fields front-loaded, followed by constraints and sequencing. No filler, though the long comma-delimited field list is slightly list-heavy for a 2-param tool.

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?

Return content, prerequisites, and security handling are covered, and no output schema exists so return format needn't be explained. The gap is parameter documentation: with 0% schema coverage on two required params, an agent lacks guidance on what draftID and controlToken are.

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 0% and there are two required parameters (draftID, controlToken), yet the description says nothing about either — no meaning, format, or sourcing for the control token. With the schema carrying no descriptions, the description fails to compensate for the coverage gap.

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 (Reads) and resource (private draft) and enumerates the returned fields: source, state, data, target display, version, expiry, preview URL. It does not explicitly contrast with update_draft or prepare_draft, but the enumeration makes its read-only retrieval role unambiguous.

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 prerequisite ("Requires the original canvas online") and a sequencing pointer ("call screenshot_draft for this version before publish_draft"), which is useful context. However, it never states when to choose read_draft over update_draft or prepare_draft, so usage is only 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.