Unavailable capabilities

What an analyst sees when a capability exists but cannot run here, for example a tool that does not run in the web build.

The model, its sequence diagram and its reference implementation are written in Phase 1. Version 0 gathers the requirements it must satisfy.

Requirements cited

SRD	Requirement
CON-10	Never fail at the point of use; show the capability with an explanation of where it is available, rather than hiding it.
TL-09	Explain why a tool is not offered.
CON-09	The web build runs Python tools in the browser; some cannot.

Model

A capability that exists but can't be used here is shown, greyed, with the reason. It is never hidden, and never left to fail at the point of use (CON-10).

Case	Where it appears	What it says
The tool doesn't apply to this selection	Tools view, Other tools	What to select: "select 2 tracks"
The tool names an unknown data type	Tools view, Not available	"It applies to contact_report, which is not a Debrief data type. Debrief knows: annotation, sensor_observations, track."
A tool library failed to load	Tools view, Not available	The library's error. The other libraries still load (TL-03).
The tool service isn't running	Tools view	"The tool service stopped. Run 'Debrief: Restart tool service'."
The catalogue is read-only	Catalogues view: lock icon, read-only	Tools that would change the plot are refused, with the reason.
A tool can't run in the browser	Phase 3, with the web build (CON-09)	Where it can run

sequenceDiagram
    participant Host as Extension host
    participant Service as Tool service
    participant Worker as Tool worker
    Host->>Service: tools/list
    Service->>Worker: describe libraries
    Worker-->>Service: tools, and unavailable with reasons
    Service-->>Host: tools; _meta debrief/unavailable
    Host->>Host: Tools view: Not available (reason)

Reference implementation

• Tools view: vscode/src/views/tools.ts. The wording of what a tool needs is in vscode/src/wording.ts.
• Reasons from discovery: debrief_tools.registry (Unavailable).