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

Annotations already establish readOnly, idempotent, and non-destructive behavior, so the description's main value is adding what the tool returns: aggregate totals by election cycle, including receipts, disbursements, contributions, cash on hand, and debts. It also implies that multiple cycles are returned by default and that the cycle parameter narrows to one, which is useful behavioral context beyond the annotations.

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 with no filler. The primary action is front-loaded, the resource and ID requirement are clear, the return fields are summarized, and the key optional filter is stated efficiently. Every sentence earns its place.

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?

For a simple read-only lookup with three well-documented parameters and no output schema, the description covers the essential semantics: what is returned, how it is grouped, and how to narrow it. Minor gaps include not stating the default number of cycles returned or whether the results include a summary/aggregate row, but these are not critical given the schema covers limit and cycle.

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 parameters are already fully described in the schema, so the baseline is 3. The description adds value by clarifying that the cycle parameter filters to a single election cycle and frames the data as cycle-level aggregates, but it does not meaningfully add semantics beyond what the schema already provides for candidate_id or limit.

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 names a specific verb ('Get'), a specific resource (aggregate campaign finance totals by FEC candidate_id), and a distinctive dimension (election cycle breakdown). It also enumerates the included fields, making the tool's purpose immediately recognizable and easily distinguishable from siblings like fec_candidate_search or fec_candidate_details.

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 no guidance on when to choose this tool over fec_candidate_details, fec_committee_search, or other FEC-related siblings. It also does not state that a user would first need to resolve a candidate to an FEC candidate_id via a search sibling, nor mention any exclusions or preferred alternatives. The only usage hint is the cycle parameter, which is a parameter instruction rather than tool-selection guidance.

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