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

With no annotations the description carries the full burden and does substantial work: it discloses the GET URL, the response contract (AuthiChain Verification Decision v1), that this host performs signature verification, and the missing-id error (presentation_not_found). It omits auth requirements and rate limits, but the behavioral picture is unusually complete for a read tool.

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?

Four tightly packed sentences, front-loaded with the cost fact and the action, with no filler. The negative scoping is compressed rather than restated.

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?

No output schema exists, so the description wisely names the return contract and the primary failure mode. Combined with full schema coverage for the lone required parameter, an agent has enough to call it correctly; only auth/rate-limit details are absent.

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 coverage is 100% and the single parameter is already described, but the description reinforces the semantics ('stored presentation id' vs. a physical scan) and complements the schema's canonical-form note. Adds meaning beyond the raw schema by tying the id to the error path.

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 and resource ('Scan a stored Living QR'), names the exact endpoint and returns, and explicitly distinguishes itself from adjacent concerns (not an x402 payment endpoint, not physical-product inspection). An agent can identify the tool's function without opening the schema.

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 positive context ('Free') and negative scoping that rules out two likely misuses, so the agent knows when this is not the right tool. It stops short of naming a specific sibling alternative for the cases it excludes, which keeps it from a 5.

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