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

Beyond the readOnly/idempotent annotations, it discloses expected latency (seconds for most products, minutes for photo books), the polling pattern, the distinction between attachable and the narrower completed signal and why they can diverge, and that design_url plus thumbnails are authoritative and must not be invented. This is far more than the annotations carry.

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 core signal (gate on attachable, not completed) is front-loaded and the structure follows a logical order from meaning to action to caveat. It is somewhat verbose, restating the attachable/completed contrast in several places, but nearly every sentence carries operational value.

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 two-parameter status poll with an output schema (so field semantics need not be re-explained), the description covers timing, polling, and the authoritative-URL rule thoroughly. The remaining gap is that the input identifiers are entirely undocumented, which matters for a tool whose whole job is to be polled with a specific pair.

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% for the two required parameters (session_id, design_id), and the description never explains what either identifier is, where to obtain it, or how session_id relates to a design_chat turn. The only adjacent hint is the mention of a design_chat turn with design_resolved=true, which does not clarify the parameter pair.

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?

The opening sentence names the exact resource and the two facts it reports: whether the design is ready to attach and whether it was locked/saved in the editor. It is distinguishable from siblings like design_chat and order_attach_design because it explicitly positions itself as the gate before order_attach_design.

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?

It gives explicit decision rules: gate checkout on attachable, never on completed; if attachable=false with thumbnails_pending=true, poll again; do NOT wait for completed. It also names the downstream tool (order_attach_design) the true condition unlocks, and warns that design_chat is refused after a save.

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