WebMCP

WebMCP gives the agent capabilities. LoadGuard decides what can change.

The page registers a small capability surface through document.modelContext. The agent gets structured planning tools, but approval authority remains outside WebMCP and is enforced server-side.

Open workspace View verification

Connected contract

7 tools

No approval tool is registered. The human approval control lives in the LoadGuard UI and records the exact staged proposal hash.

Consequence tiers

The tool surface is deliberately narrow

Read only

Inspect current state, constraints, and audit events without changing proposals or active load.

get_load_state
get_package_constraints
get_action_ledger

Candidate state

Create, validate, and stage proposal snapshots that remain separate from active truck state.

create_load_plan
validate_load_plan
stage_load_plan

Operational

Request execution of an already approved proposal. The database still decides whether it is allowed.

commit_load_plan

Tool inventory

Exactly seven tools are exposed

Tool	Purpose	Consequence
get_load_state	Inspect truck state	READ ONLY
get_package_constraints	Inspect package constraints	READ ONLY
create_load_plan	Build candidate plan	CANDIDATE
validate_load_plan	Validate candidate	CANDIDATE
stage_load_plan	Stage immutable proposal	CANDIDATE
commit_load_plan	Apply approved proposal	OPERATIONAL
get_action_ledger	Inspect audit events	READ ONLY

Contract

The tool submits intent. Authority evaluates it.

Commit accepts

commit_load_plan({
  "proposal_id": "PLAN_PROPOSAL_UUID"
})

Commit does not accept

commit_load_plan({
  "coordinates": "...",
  "approval": true,
  "force": true
})

Approve proposal and reject proposal are not WebMCP capabilities.

This asymmetry is deliberate. The agent can ask for execution, but the application and database verify whether the operator already authorized that exact staged plan.

Expected responses

The boundary is observable

Before approval

{
  "ok": false,
  "code": "APPROVAL_REQUIRED",
  "status": "STAGED"
}

After approval

{
  "ok": true,
  "status": "EXECUTED",
  "state_revision": 2
}

Replay

{
  "ok": false,
  "code": "ALREADY_EXECUTED",
  "status": "EXECUTED"
}