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

Annotations declare readOnlyHint=false and idempotentHint=false, meaning the call may write state, yet the description reads like a pure calculation and says nothing about side effects, ledger writes, or idempotency. With annotations covering safety but the description implying a read-only computation, the agent gets no added behavioral context and may be misled about mutation.

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 core calculation, with no filler. The carbon_accountable clause is somewhat cryptic and partially redundant given the output schema, but the overall structure is efficient.

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?

Although an output schema exists (so return values needn't be explained), this is a two-parameter tool with 0% schema description coverage and a non-read-only annotation. The description does not explain buyer semantics, emitted_g units, or what state (if any) the call changes, so an agent lacks enough context to invoke it confidently.

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%, so the description must compensate for both parameters. It partially explains emitted_g by noting it comes from the agent-compute-ledger, but never clarifies the buyer parameter or the unit/format of emitted_g, leaving the schema gap largely unfilled.

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 calculation (emitted minus retired) tied to a buyer and a ledger, which identifies the resource. However, it lacks an action verb (compute? record? fetch?) and does not distinguish the tool from siblings such as get_purchase or verify_retirement, leaving the agent to infer that this computes a net position rather than records one.

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 guidance on when to use this tool versus alternatives like buy_offset or verify_retirement, nor any prerequisites or exclusions. The sentence about carbon_accountable implies a post-offset check, but usage context is only weakly implied.

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