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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), and the description adds genuinely non-redundant behavior: an external dependency on the canvas being online, and a sensitivity warning that previewURL must be kept private. It does not describe failure modes or expiry semantics beyond naming the field.

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 no filler; the capability list comes first and the constraints follow. Listing returned fields rather than actions is slightly unusual but efficient given there is no output schema.

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?

With no output schema, the description usefully enumerates returned fields, plus precondition, privacy note and sequencing. The missing piece is any explanation of controlToken and how a caller obtains it, which matters for a tool on a private resource.

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%, so the description carries the full burden, yet it never mentions either parameter. draftID is inferable from context, but controlToken — evidently a credential gating access to a 'private' draft — is left entirely unexplained, which is a real gap for a 2-required-param tool.

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?

Uses a specific verb ('Reads') on a specific resource ('a private draft source') and enumerates exactly what comes back — state, data, target display, version, expiry, previewURL. That is enough for an agent to separate it from update_draft/publish_draft/discard_draft, though it never explicitly contrasts with read_component, the nearest sibling.

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?

States a hard precondition ('Requires the original canvas online') and gives ordering guidance ('call screenshot_draft for this version before publish_draft'). It stops short of saying when not to use it or what to do if the canvas is offline.

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