feat: add docker_exec MCP tool for ergonomic container commands on LXCs

- New MCP tool wraps  with proper escaping
- Resolves LXC target from entity graph (no hardcoded IPs)
- Uses classifyAndGate for classification + approval chain
- Read-only commands (curl GET, cat, ls) auto-execute
- Mutations (POST/PUT/DELETE) require operator approval
- Full audit trail via execution rows
- Updates AGENTS.md with tool listing

AGENTS.md

@@ -92,6 +92,7 @@ elsewhere; regenerate from `internal/mcp/` when tools change):
     ping_service(service_slug) — HTTP reachability + scheduler health state
     list_lxcs(state) — all LXC containers with ID, host, IP, last-audited hint
     restart_service(target, service) — restart a systemd service (config_mutation, requires approval)
+    docker_exec(lxc_slug, container, command, purpose) — run a command inside a Docker container on an LXC; handles escaping, resolves target from entity graph; read-only auto-runs, mutations require approval
     push_file(target, source_path, dest_path, backup=true) — push a file into an LXC from the Proxmox host (config_mutation, requires approval)
     ack_signal(signal_id) — acknowledge an open signal
     resolve_signal(signal_id, resolution) — resolve a signal with optional note

internal/mcp/ops_tools.go

@@ -47,6 +47,58 @@ func OpsTools(pool *db.Pool, agentID uuid.UUID, sec secretBackend) []toolReg {
 					}
 		
 					return classifyAndGate(ctx, pool, agentID, targetID, targetSlug, command, purpose, declaredRisk, sessionID), nil
+				}},
+				// docker_exec wraps a command inside a Docker container on an LXC.
+			// Resolves the LXC, looks up the pve_id, and runs via
+			// `pct exec <pve_id> -- docker exec <container> sh -c '...'`.
+			// Uses the same classifyAndGate safety path as `run`.
+			{tool: &mcp.Tool{Name: "docker_exec", Description: "Run a shell command inside a Docker container on an LXC. Use when you need to query an app's REST API inside a docker container (curl, Sonarr/Radarr API calls), read its logs or config from inside the container, or make config changes. This is the ergonomic replacement for `run(target, 'docker exec <container> ...')` — it handles command escaping, container resolution, and classification. Commands that mutate container state (POST/PUT/DELETE /api/, file writes) classify as config_mutation and require approval. Reads (GET, cat, ls, status checks) auto-run.",
+				InputSchema: objSchema(
+					prop{"lxc_slug", "string", "LXC entity slug (e.g. lxc:arriman, lxc:caddy). The LXC must be active and running Docker."},
+					prop{"container", "string", "Docker container name inside the LXC (e.g. prowlarr, sonarr)."},
+					prop{"command", "string", "The shell command to run inside the container. Runs via `docker exec <container> sh -c '...'`. Shell escaping is handled for you."},
+					prop{"purpose", "string", "One sentence: why you're running this. Shown alongside any approval request."},
+					prop{"declared_risk", "string", "Optional self-assessment: read_only, config_mutation. Override the auto-classification."},
+				),
+			}, handler: func(ctx context.Context, req *mcp.CallToolRequest) (*mcp.CallToolResult, error) {
+				args := argsMap(req)
+				lxcSlug, _ := args["lxc_slug"].(string)
+				container, _ := args["container"].(string)
+				command, _ := args["command"].(string)
+				purpose, _ := args["purpose"].(string)
+				declaredRisk, _ := args["declared_risk"].(string)
+				sessionID, _ := args["_session_id"].(string)
+
+				if lxcSlug == "" || container == "" || command == "" {
+					return textResult("error: lxc_slug, container, and command are required"), nil
+				}
+				if purpose == "" {
+					return textResult("error: purpose is required"), nil
+				}
+
+				// Normalize slug prefix
+				if !strings.HasPrefix(lxcSlug, "lxc:") {
+					lxcSlug = "lxc:" + lxcSlug
+				}
+
+				// Look up the LXC entity
+				var targetID uuid.UUID
+				var pveID string
+				if err := pool.QueryRow(ctx,
+					`SELECT id, COALESCE(attributes->>'pve_id', '') FROM entities WHERE slug = $1`,
+					lxcSlug).Scan(&targetID, &pveID); err != nil {
+					return textResult(fmt.Sprintf("LXC not found: %s", lxcSlug)), nil
+				}
+				if pveID == "" {
+					return textResult(fmt.Sprintf("LXC %s has no pve_id attribute — can't resolve Proxmox host", lxcSlug)), nil
+				}
+
+				// Escape the command for safe sh -c '...' inside docker exec.
+				// The standard trick: replace ' with '\'' then wrap in single quotes.
+				noQuote := strings.ReplaceAll(command, "'", "'\\''")
+				dockerCmd := fmt.Sprintf("docker exec %s sh -c '%s'", container, noQuote)
+
+				return classifyAndGate(ctx, pool, agentID, targetID, lxcSlug, dockerCmd, purpose, declaredRisk, sessionID), nil
 			}},
 				// inspect_path is the bulk fact-gathering tool from
 				// plans/2026-07-18-session-review-three-sessions.md P1.5.