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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world, so safety is covered. The description adds genuinely non-annotated context: the authentication requirement to connect a TrimCarbon account. It does not cover error cases or pagination/rate limits, keeping it short of a 5.

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 sentences, front-loaded with the operation and its key output, followed by the prerequisite. The enumeration of returned fields is somewhat redundant given the tool has an output schema, which slightly dilutes density.

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?

With an output schema present, the description does not need to justify return values, yet it conveniently summarizes them. Auth requirement and parameter provenance are both covered, so an agent has everything needed to invoke this single-parameter read tool correctly.

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% with an example value already in the schema, so the baseline is 3. The description adds provenance meaning beyond the schema by stating the identifier is the one returned by list_my_offsets, which helps the agent locate a valid value rather than guess.

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 ('Shows one of the signed-in user's TrimCarbon certificates') and enumerates the returned content (CO₂, holder, dates, projects, serial numbers, links). It also distinguishes itself from the sibling list_my_offsets by naming it as the producer of the required identifier.

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?

Explains where the certificate number comes from ('that list_my_offsets returns') and states the prerequisite ('Needs the user to connect their TrimCarbon account'). It gives clear context for when this tool applies, though it stops short of explicitly naming conditions where another tool would be the better choice.

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