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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the bar is low. The description adds genuinely useful context by defining the two result sets and how depth/direction shape the traversal, which is behavioral detail absent from the annotations. It stops short of noting graph-size or truncation behavior on deep transitive walks.

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 compact sentences with the primary output explanation front-loaded and parameter modifiers trailing. No redundant scaffolding or filler; every clause carries meaning.

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 correctly shoulders the burden of explaining return values and does so clearly via the precedents/dependents framing. Combined with fully documented parameters and strong annotations, an agent has what it needs; only edge behavior for deep or cyclic graphs is left implicit.

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% and every parameter already carries its own description, so the baseline is 3. The description largely restates depth and direction semantics that the schema documents, adding only the intuitive framing of 'walks transitively' versus 'direct only'.

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 pairs a specific verb ('Returns... dependency graph') with a precise resource and defines both output halves (precedents/dependents). The Excel trace-precedents analogy makes the concept unambiguous, though no sibling tool is named for contrast even though layerz_diff and layerz_read are nearby in scope.

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?

Usage is implied rather than stated: an agent can infer this is for impact analysis and formula tracing, but the description gives no explicit when-to-use versus layerz_diff/layerz_read, and no exclusions or prerequisites (such as the model_id requirement for user-scoped keys, which lives only in the schema).

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