lineage_why

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds meaningful behavioral context beyond that: it discloses that input can be 'a slug id or free text', that it returns 'the lineage, not a blob', and that it synthesizes a plain-language answer. These details help the agent anticipate the tool's output shape and processing behavior without contradicting 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?

Three sentences, each earning its place: the first states purpose, the second details input and output, and the third gives usage timing. There is no filler or repetition; the description is front-loaded with the core question and communicates a dense amount of useful information efficiently.

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 description covers most of what an agent needs: purpose, query semantics, return contents, and usage context. However, it omits any explanation of the required app_id parameter, and since there is no output schema, the description must carry the full burden of return-value documentation. It does explain return contents well, but the app_id gap is a notable incompleteness for a required parameter.

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 0%, so the description must compensate. It explicitly explains the query parameter ('Give a slug id or free text') but says nothing about app_id, which is required. The query semantics are clear, but app_id remains ambiguous, leaving a gap in parameter understanding. Partial compensation for one of two parameters merits a 3.

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 the exact question the tool answers ('why does X exist / where did X come from') and names the resource (recorded lineage). It then specifies the output contents (rationale, origin, authority, evidence, typed edges) and positions the tool as a distinct lookup verb ('This is the verb a curious agent runs before acting'), making it clearly distinguishable from lineage_list and lineage_record even without naming them.

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 a clear usage context: 'This is the verb a curious agent runs before acting on something it didn't build.' This tells the agent when to use the tool (pre-action discovery) but does not explicitly name alternatives or state when not to use it. The guidance is implicit rather than comparative, so it misses the top score but provides enough context.

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