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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description contributes the lineage-chain structure and the account prerequisite, adding useful context beyond the annotations, though it doesn't describe output format or pagination.

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, zero waste, with the operation and its chain steps front-loaded before the auditor rationale and prerequisite. Nothing extraneous.

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 read-only, two-parameter tool with no output schema, the description conveys enough: what the lineage chain contains, the account requirement, and the auditing purpose. Return shape is not specified but no output schema exists, so a minor gap.

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 100%, so both parameters (source_transaction_id and optional agreement_id) are fully documented in the schema. The description only adds 'for a given transaction,' which is baseline-level value when the schema does the heavy lifting.

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 concrete operation — walking an accrued figure back through the lineage chain (source row → eligibility → bucket → rate → rule → event chain) for a given transaction. This is a distinct verb+resource that clearly separates it from compute_*, analyze, and explain 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?

Provides a clear use case ('how you show an auditor exactly why a number is what it is') and a prerequisite ('Requires a connected Aurgus account'). It doesn't explicitly exclude or contrast with siblings like explain or analyze, so a 4 rather than 5.

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