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

Annotations already declare readOnlyHint=false, idempotentHint=true, destructiveHint=false, openWorldHint=false, so the safety envelope is covered. The description adds genuine value beyond that: it discloses the return shape (rewritten operation or original), a non-obvious 'candidate withholding' behavior, a verification-status field, and hard limits ('local software evidence only', 65536 request bytes). That is substantive behavioral context.

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 Problem/Input/Result/Limits framing is front-loaded and wastes no words. It is telegraphic but every clause carries information, and scoping limits are placed last as expected. Minor cost is that the terse style reads like a contract rather than task activation.

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?

An output schema exists, so explaining return values is not strictly required, and the description covers result and limits. However, for a non-read-only tool carrying a max_total_price const and idempotency_key, the description never addresses cost/purchase semantics or when the job-spending path applies, which is an important context gap for a complex mutating tool.

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% across 4 required parameters, so the description must carry the burden. It only loosely points at the payload ('operation, target gate, phase context') while the actual required envelope — schema_version, request, idempotency_key, and especially max_total_price — is never explained. The price field is the most consequential one and is left entirely opaque, so compensation is inadequate.

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 gives a specific verb and resource: 'Rewrite this supported circuit under the supplied phase-equivalence and target constraints.' That is clear and more precise than a tautology. It stops short of naming which sibling tool to prefer (e.g., quantum_supported_circuit_equivalence_v1 or quantum_two_qubit_target_synthesis_v1), so the agent must infer the boundary itself.

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?

There is no explicit when-to-use or when-not-to-use guidance. The phrase 'supported circuit' and 'phase-equivalence constraints' implies a context, but among ~40 quantum siblings the description never states the condition that selects this rewrite tool over the equivalence, synthesis, optimization, or inspection tools. The agent is left to guess.

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