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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower. The description adds real behavioral context on top: the required permission ('project Read'), the default walk-every-side behavior, and notably the truncation disclosure ('with how many the limit left out'), which tells the agent results may be partial.

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, front-loaded with what is returned before the permission note. The edge-reading parenthetical and truncation clause each add distinct value. Slightly dense, but nothing reads as 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?

With no output schema, the description carries the return-value burden and does so: it describes nodes, edges, edge direction, and truncation count, plus the auth requirement. Missing only ordering/pagination detail for the returned nodes, which would fully close the loop.

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%, so baseline is 3, but the description earns above it: it explains the edge reading convention ('derivedId was built from inputId'), which is response semantics for the graph, and clarifies the default traversal ('Walks every side by default') that governs revealAll/reveal behavior without restating the schema.

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 specific verb+resource: the memory's lineage, split into upstream ('what a memory was built from') and downstream ('what was built on it'), plus the exact edge semantics ('derivedId was built from inputId') and the limit-truncation count. That is far more than a restatement of the name. It does not name a sibling (e.g. get_trace_node, find_trace_roots) to contrast against, so it stops short of a 5.

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 use case is implied by 'Mirrors Trace's Lineage tab', and the prerequisite 'needs project Read' is given, along with the default traversal behavior. But there is no explicit when-to-use guidance versus the trace-node/root-finding siblings, so the agent must infer the routing decision itself.

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