set_purchase_order

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

With no annotations present, the description carries the full burden, and it does disclose the important trait that this is preview-first and that apply is currently disabled. That is useful context. However, it omits behavior around dryRun defaults, previewToken lifecycle, idempotencyKey, the various expected* hash guards, and what happens to the entity on apply.

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 short sentences, front-loaded with the most important context (preview-first, apply unavailable), with no filler. It is tight, though it errs toward under-specification rather than over-verbosity.

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 high-complexity mutation tool with 10 undocumented parameters, optimistic-concurrency hashes, and no output schema, two sentences are far from sufficient. An agent lacks the preview/apply workflow, hash semantics, and any parameter meaning needed to invoke it safely.

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?

There are 10 parameters with 0% schema description coverage, and the description explains none of them. Critical parameters like previewToken, idempotencyKey, expectedDesiredHash, expectedSemanticHash, expectedWriteShapeHash, and expectedEntityTimestamp are entirely opaque, leaving an agent unable to supply them correctly.

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 description frames the tool as a 'preview-first replacement for the deprecated immediate purchase-order write,' which identifies the resource (purchase order) and hints at a mutation intent. However, it never states what the tool actually does in its current state (a preview, since apply is unavailable), and the verb 'set' is only implied. It is distinguishable from siblings only loosely.

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 notes that the apply path is unavailable until the domain adapter and canary are complete, which is a genuine usage caveat. But it gives no guidance on when to use this versus upsert_purchase_order or set_purchase_order_receipts, and no prerequisites or triggers for the preview path.

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