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 by structured data. The description adds one useful behavioral fact — that each trace may map to multiple runs in multi-agent setups — but says nothing about permissions, the superadmin customerId path, or result limits, so added value is modest.

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 defines the operation and its output shape, the second gives a concrete usage scenario, and the third flags the multi-run multiplicity caveat. The core purpose is front-loaded with no filler.

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?

There is no output schema, so the description must carry the return-shape burden — and it does, explicitly naming ancestors, self, and children. Combined with the multi-agent caveat and annotations covering read-only safety, an agent has everything needed to call this correctly.

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 (traceId, customerId) are already documented in the schema, including the superadmin-only note on customerId. The description only restates that lineage is resolved for the traceId and adds no syntax, format, or edge-case detail beyond that. Baseline 3 applies 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?

The description names a specific verb (get), the exact resource (runtime trace lineage for a traceId), and enumerates the three parts of the result: ancestors, the trace itself, and children. This makes it immediately distinguishable from siblings like get_run or get_run_finding_context, which operate on runs rather than trace lineage.

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?

It gives a clear when-to-use signal: 'Use this to navigate multi-trace workflows, for example a design run that spawned an interview run.' However, it does not name any alternative tool (e.g., get_run) or state when-not to use this one, so the routing guidance stops short of explicit exclusions.

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