Runtime capabilities

Understand the filesystem, command, process, and observation capabilities Jio exposes inside a sandbox.

The Jio runtime performs the effects requested through MCP. It turns a structured tool call into a bounded filesystem or process operation inside the selected sandbox, then returns evidence the agent can reason about.

Capability groups

CapabilityTypical effects
Workspace statusReport sandbox identity, lifecycle, and effective policy
Discovery and readList paths, inspect metadata, search text, and read files
WriteCreate, update, move, and remove workspace files
Command executionStart a command with a working directory, environment, and timeout
Process observationStream or collect output, exit status, duration, and truncation state
Version controlInspect status, diffs, history, and project-scoped changes

Deployments should expose only the capability groups a workflow needs. Supporting execution at the runtime level does not mean every session must receive it.

One request, one observable result

Validate the target

Resolve paths and working directories against the selected sandbox before creating an effect.

Apply policy

Check the session's capability, approval state, resource limits, and network rules.

Perform the operation

Run the filesystem or process action inside the remote environment.

Return evidence

Report success, bounded output, exit status, duration, or the rule behind a rejection.

Capability versus permission

An unavailable capability and a denied request are different states:

  • Unavailable means the runtime did not expose the tool to this session.
  • Denied means the capability exists, but policy rejected this operation.

That distinction helps an agent change strategy without repeatedly attempting an action it cannot perform.

See the MCP tools reference for the capability contract and configuration for the policy concepts that constrain it.

On this page