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

Goes beyond the readOnlyHint by disclosing that PII values are masked, that masking is represented via maskedKeys, and that unmasked values are only available through an audited console path. This is meaningful behavioral information for an agent handling sensitive data.

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?

One dense sentence front-loaded with the core action and resource, followed by a compact enumeration of response contents. All clauses add information, though the long comma-separated list slightly reduces skimmability.

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 no output schema, the description compensates well by enumerating the major returned components: decision outcome, per-rule rationale, responsibility chain, masking behavior, and snapshot fingerprint. An agent can predict the response shape well enough to call the tool safely. Minor omissions like error behavior are acceptable for a simple get-by-ID tool.

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 single parameter traceId is already documented in the schema, and the description adds little about how to obtain or validate a traceId. Schema coverage is effectively complete, so the baseline of 3 is appropriate.

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 opens with a specific verb and resource ('Get the lineage of a single decision') and enumerates the key components returned. It is clearly distinct from broader history or listing tools, though it does not explicitly name sibling alternatives.

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: an agent should call this when it needs decision-level provenance rather than general history or logs. However, it does not explicitly state when to prefer this over lexq_history_get or lexq_logs_get, so routing to the right sibling is left to inference.

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