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

With no annotations, the description carries the burden of behavioral disclosure. It states the tool aggregates and that totals are exact sums, implying a purely computational, read-only operation with no side effects. However, it does not explicitly declare itself as read-only or mention error cases (e.g., unknown agent), leaving a small gap.

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 one sentence that front-loads the key action and lists the output metrics. Each phrase earns its place, and there is no redundant or filler content.

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 simple with one parameter and an output schema (not shown but present). The description covers what it does, what it returns (the five metrics), and that sums are exact. For a read-only aggregation tool, this is sufficient context without needing to explain return values, which the output schema handles.

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 has only agent_id with a title 'Agent Id', and schema coverage is 0%. The description says 'for an agent,' which directly ties the parameter to the tool's purpose, adding meaning beyond the schema. While it doesn't detail formatting or allowed values, the single parameter is self-explanatory and the description clarifies its role.

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 clearly states the tool aggregates footprint data for an agent, listing specific metrics (J, kWh, gCO2e, cost, mean Landauer efficiency). The verb 'Aggregate' and resource 'footprint for an agent' are specific and distinguish it from sibling tools like list_entries or record_work.

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 implies usage by stating it aggregates totals from ledger entries, but does not explicitly mention alternatives or when not to use it. It says 'Totals are exact sums of the ledger entries,' which hints at list_entries for raw data, but without an explicit directive, the usage context is only implied.

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