The CLI already tracked token usage, but it did not translate that usage into model-aware cost reporting or offer a spend guardrail. This change adds a max-cost flag, integrates estimated USD totals into /status and /cost, emits near-budget warnings, and blocks new turns once the configured budget has been exhausted.
The workspace verification request also surfaced stale runtime test fixtures that still referenced removed permission enum variants, so those test-only call sites were updated to current permission modes to keep full clippy and workspace test coverage green.
Constraint: Reuse existing runtime usage/pricing helpers instead of adding a new billing layer
Constraint: Keep the feature centered in existing CLI/status surfaces with no new dependencies
Rejected: Move budget enforcement into runtime usage/session abstractions | broader refactor than needed for this CLI-scoped feature
Confidence: high
Scope-risk: moderate
Reversibility: clean
Directive: If resumed sessions later need historically accurate per-turn pricing across model switches, persist model metadata before changing the cost math
Tested: cargo fmt --all --check; cargo clippy --workspace --all-targets -- -D warnings; cargo test --workspace
Not-tested: Live network-backed prompt/REPL budget behavior against real Anthropic responses
The Rust CLI/runtime now models permissions as ordered access levels, derives tool requirements from the shared tool specs, and prompts REPL users before one-off danger-full-access escalations from workspace-write sessions. This also wires explicit --permission-mode parsing and makes /permissions operate on the live session state instead of an implicit env-derived default.
Constraint: Must preserve the existing three user-facing modes read-only, workspace-write, and danger-full-access
Constraint: Must avoid new dependencies and keep enforcement inside the existing runtime/tool plumbing
Rejected: Keep the old Allow/Deny/Prompt policy model | could not represent ordered tool requirements across the CLI surface
Rejected: Continue sourcing live session mode solely from RUSTY_CLAUDE_PERMISSION_MODE | /permissions would not reliably reflect the current session state
Confidence: high
Scope-risk: moderate
Reversibility: clean
Directive: Add required_permission entries for new tools before exposing them to the runtime
Tested: cargo fmt; cargo clippy --workspace --all-targets -- -D warnings; cargo test -q
Not-tested: Manual interactive REPL approval flow in a live Anthropic session
