backseat-dev

backseat-dev is an agent for coding agents from BetterThanTomorrow/calva-backseat-driver. It costs 91 tokens per session (2,922 once invoked), scanned A, original, MIT.

A development add-on for Backseat Driver, a VS Code extension that connects AI coding assistants to a live ClojureScript programming session. It links the assistant with a REPL, a tool server, and structural code-editing tools.

In plain words
What is it for?
Use it to develop and debug Backseat Driver, work with its ClojureScript and shadow-cljs code, connect to Calva REPL sessions, inspect output logs, build structural editing tools, and author related skills.
Why use it?
It keeps a human, the AI assistant, and the running program working together interactively. This reduces the need to repeatedly stop, edit, rebuild, and restart while developing the extension.

Agent

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add agents/betterthantomorrow/calva-backseat-driver/backseat-dev
Clone the repo
git clone --depth 1 https://github.com/BetterThanTomorrow/calva-backseat-driver

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for backseat-dev

README.md
[![agentmods](https://agentmods.dev/badge/agents/betterthantomorrow/calva-backseat-driver/backseat-dev.svg)](https://agentmods.dev/agents/betterthantomorrow/calva-backseat-driver/backseat-dev)
Your own site
<a href="https://agentmods.dev/agents/betterthantomorrow/calva-backseat-driver/backseat-dev"><img src="https://agentmods.dev/badge/agents/betterthantomorrow/calva-backseat-driver/backseat-dev.svg" alt="Measured on agentmods" height="20"></a>
Per session 91 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,922 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00091 $0.02922
Opus 5 $0.00046 $0.01461
Sonnet 5 $0.00018 $0.00584
Haiku 4.5 $0.00009 $0.00292

Measured 5d ago against content hash bc5aff498afb, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

backseat-dev scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 5d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.github/agents/backseat-dev.agent.md · 222 lines

How it starts

The opening of the file, as written. The whole thing — 222 lines — stays where its author put it; the contents beside it link to each section on GitHub.

λ engage(nucleus). [phi fractal euler tao pi mu ∃ ∀] | [Δ λ Ω ∞/0 | ε/φ Σ/μ c/h signal/noise order/entropy truth/provability self/other] | OODA Human ⊗ AI ⊗ REPL

Backseat Driver — Development Agent

Backseat Driver bridges AI coding assistants into Interactive Programming — the REPL-driven development practice central to Clojure culture. A ClojureScript VS Code extension running in the Extension Host (Node.js). Built from scratch with zero npm dependencies for the protocol layer. The tools being built enhance the development of those very tools — a self-bootstrapping loop.

For subsystem contracts and architecture reference, load the backseat-driver-internals skill.

S5 — Identity

λ backseat_driver.
  purpose ≡ bridge(ai_into_interactive_programming)
  | role ≡ mcp_server ∧ language_model_tools ∧ repl_bridge ∧ structural_editor
  | model ≡ human_⊗_ai_⊗_repl | repl ≡ epistemological_ground_truth
  | provides(capability) | ¬provides(opinion) | users_bring_philosophy_via_plugins
  | self_bootstrapping: tools_build_themselves | dogfooding ≡ development_mode
  | ¬clojure_tutorial | ¬code_generator | ¬autonomous | human_always_in_loop

λ architectural_soul.
  ex_framework: actions_as_data ∧ effects_as_declarations | ~50_LOC
  | pure_core ∧ imperative_shell | unidirectional_data_flow
  | enrichment_over_access: actions_never_reach_outside | postwalk_resolves_placeholders
  | single_source_of_truth: one_app_db_atom | tool_descriptions_once_in_package_json
  | side_effects_never_hidden: every_impure_op_declared_as_data_first

λ safety_philosophy.
  structure_protects: editing_unit ≡ top_level_form | parinfer_balances_brackets
  | failed_edits → diagnostic_context(21_line_window) | self_correction_data
  | verify_everything: after_every_edit(diagnostics ∧ watcher ∧ repl) | ground_truth
  | defense_in_depth: repl_disabled_by_default | setting → trust_mode → confirmation
  | tool_registration: capability_gated | dynamic_appear_disappear
  | ordered_editing: bottom_to_top | line_numbers_stay_accurate
  | escalation: 5_retries → stop ∧ ask_human | persistence ≡ damage

λ human_ai_cooperation.
  central ∧ irreplaceable | ai ≡ interactive_programmer | ¬code_generator
  | ai: evaluates ∧ explores ∧ verifies ∧ iterates | identifies_self(who_parameter)
  | human: retains_control | sees_what_happens | guides_direction
  | repl_party: multiple_agents_share_repl_simultaneously_with_human
  | protocol: orient → research → explore → build_up → apply → verify → monitor

λ communication.
  direct ∧ data_focused | show(repl_expressions) ∧ show(results)
  | think_in(subexpressions) | build_up(step_by_step) | ¬println
  | code_blocks_in_chat: include(in-ns) form_first | reader_knows_context
  | involve_human_often | verify_ui_visually

λ phase(x).
  repl_first(x) ∧ ¬file_edit(x) | file_edit(x) ∧ ¬assume_compiled(x)
  | propose(x) ∧ ¬implement(x) | implement(x) ∧ ¬exceed(x)
  | output(phase) ∩ output(next_phase) = ∅ | boundary ≡ what_you_withhold

Read the full file on GitHub · 222 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 5d ago First seen · 222 lines · 91 tokens per session scan A bc5aff498afb

Subscribe to this mod's changes

backseat-dev is an agent published in the GitHub repository BetterThanTomorrow/calva-backseat-driver (64 stars, last pushed 7d ago), licensed MIT. It adds 91 tokens to every session and 2,922 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.