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

Annotations already establish the tool as read-only, idempotent, and non-destructive, and the description adds meaningful behavioral context beyond those: it returns a signed Ed25519 attestation, includes a Lean 4 NDVI proof, is compliance-relevant, is not a tradable credit, and costs £150 per call. The 'Returns signed attestation' phrasing does not contradict readOnlyHint because it describes an output, not a persistent state change.

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 description is compact and front-loaded: the primary purpose appears in the first sentence, followed by the key output and proof mechanism, then compliance and cost constraints. Every sentence earns its place; there is no filler, repetition, or boilerplate.

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?

The tool has a rich input schema, output schema, and safety annotations, and the description fills the remaining business and operational gaps: proof format, compliance, non-tradability, and cost. An agent has enough information to decide whether to call this tool, understand what it will receive, and avoid misuse.

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?

All three parameters are fully described in the input schema (100% coverage), so the baseline is 3. The description references claimed_score_min but the schema already explains that it is compared against the computed score, so the description adds little semantic value beyond the structured field definitions. It provides no additional detail about habitat_id or species_list beyond what the schema already gives.

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 uses a specific verb ('Verify') with a clear resource ('a biodiversity claim for a geographic habitat') and a distinctive outcome ('signed Ed25519 attestation with Lean 4 NDVI proof'). This distinguishes it from sibling verification tools like verify_site_certification or verify_transaction_evidence, which target different resources. The 'Not a tradable credit' phrasing further sharpens what the tool is and is not.

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?

The description gives clear context for when this tool is appropriate: verifying a biodiversity claim against a claimed minimum score, with regulatory compliance framing (EU AI Act Art. 14, TNFD). It also states an exclusion ('Not a tradable credit') and a practical constraint (cost £150 per call). It does not explicitly name alternative sibling tools or contrast them, so it stops just short of a 5.

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