Commands and keys

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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the safety profile is covered. The description adds real behavioral context beyond that: results are scoped to the current focus location, several command sources are merged, and an unbound key is reported as going 'straight to the application' rather than failing.

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 sentences with the primary behavior front-loaded and no filler. The clause 'like the Input Gestures dialog: NVDA's own, add-ons', the app module's and the focused control's' is slightly list-heavy and reads a bit awkwardly, but every element carries information.

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 an output schema present, return-value detail is unnecessary, and annotations cover safety. The description supplies the focus-scoping caveat and multi-source coverage that an agent needs to interpret results; only minor items like result ordering or whether unassigned commands are included are unstated.

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 the baseline is 3. The description nonetheless adds meaning by framing 'key' as a mode switch that replaces enumeration with a single lookup and by explaining what the returned answer means when no command is bound, which is not stated in 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 and resource ('List the NVDA commands available where focus is now, with their keys') and enumerates the sources covered: NVDA's own, add-ons', the app module's and the focused control's. The alternate lookup mode is also named, so an agent can tell exactly what this tool returns, and no sibling in the list offers anything comparable.

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 explains the two modes (list mode vs. 'With key, say which command a key runs here'), which is genuine mode-selection guidance. However, it never says when to reach for this over related siblings such as nvda_press_keys or nvda_run_script, nor when not to use it; usage is implied rather than stated.

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