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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description aligns by stating 'this server never performs the retirement and never holds a wallet.' It adds valuable context about keyless payment from the caller's wallet and the orientation of footprint numbers, going beyond the annotation hints to clarify behavioral boundaries.

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 somewhat verbose, with extra philosophical commentary about the validity of carbon claims. While the main purpose is front-loaded, the sentence about footprint orientation feels tangential and could be trimmed. It is not as tight as it could be, but it is not excessively long.

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 is moderately complex with an output schema and multiple parameters. The description explains the operational model (keyless, caller wallet, certificate), distinguishes it from actual retirement execution, and provides enough context for the agent to understand the tool's role. The output schema covers return details, so no major gaps remain.

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?

The schema provides 100% coverage for all three parameters, so the baseline is 3. The description mentions amount_tco2e only indirectly ('a given tCO2e amount') and does not add syntax or usage details beyond the schema. It does not compensate for any gaps, but since coverage is complete, no further compensation is needed.

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 states a specific verb and resource ('retire a given tCO2e amount') and clarifies it returns a confirmed retire transaction as the certificate, distinguishing it from other tools that perform actions directly. It explicitly notes the server does not perform the retirement itself, which differentiates it from submit-class siblings.

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 explains what the tool does and implies it is used when the caller wants to retire carbon and receive a certificate, but it does not explicitly state when not to use it or name alternative tools. The phrase 'this server never performs the retirement' gives a hint about its non-execution nature, but there is no explicit comparison to siblings like submit_claim or prepare_claim.

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