list_features

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

No annotations exist, so the description carries the full burden. It usefully discloses two behavioral traits beyond a bare listing: it flags features that fail to rebuild and names sketches that are not fully defined. However, it says nothing about what happens when no part is open (error vs empty), whether hidden/suppressed-only filtering applies, or ordering guarantees beyond 'tree order'.

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 short, front-loaded sentences; the returned fields are given first and the use case second, which is the right order for scanning. The mid-sentence line break adds a little visual noise but no content waste.

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 and no annotations, the description must stand alone, and it does state the returned attributes and two special diagnostics. It is complete enough to call correctly, though it omits edge-case behavior (no open part, empty history).

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 tool takes zero parameters, so there is nothing for the description to disambiguate and the baseline of 4 applies. There is no parameter information to omit or misstate.

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 (list) and resource (the current part's modelling history) plus the exact returned fields (name, type, suppressed). This clearly separates it from the other list_* siblings (list_dimensions, list_faces, list_edges), which return different entity types.

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?

Gives concrete usage contexts: 'For a part opened from disk, or to find the step to undo.' This implies when to reach for it without naming an alternative tool. It does not route the agent explicitly to delete_feature/suppress_feature for acting on the listed history, so it falls short of a full when/when-not statement.

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