executor

An implementation agent for carrying out software tasks using TDD, or test-driven development, where tests are written to guide the code.

In plain words
What is it for?
Use it to execute coding tasks, follow a test-guided workflow, record task progress, verify results, and work with repository files and commands.
Why use it?
It keeps implementation work organized through task notes, verification, and synchronization practices.

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/cofin/flow/executor
Clone the repo
git clone --depth 1 https://github.com/cofin/flow
Per session 20 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 338 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 $0.00020 $0.00338
Opus 5 $0.00010 $0.00169
Sonnet 5 $0.00004 $0.00068
Haiku 4.5 $0.00002 $0.00034

Measured yesterday against content hash e61c71d16524, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

executor 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 yesterday.

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/executor.agent.md · 44 lines

What it actually says

{
  "canonical_id": "executor",
  "canonical_source": "agents/executor.md",
  "git_tags": "forbidden",
  "host": "vscode_copilot",
  "instruction": "Read and follow the canonical agent source directly.",
  "interaction_requirement": "none",
  "invariant_ids": [
    "worksheet-execution-v1",
    "flow-state-v1",
    "git-no-tags-v1"
  ],
  "kind": "flow_agent_adapter",
  "question_capability": {
    "bounds_enforcement": "unsupported",
    "choice_max": null,
    "choice_min": null,
    "custom_answer_behavior": "sequential_text_only",
    "disabled_choice_policy": "omit",
    "evidence": "No verified Flow-native VS Code Copilot question tool",
    "multi_select": false,
    "mutual_exclusion": false,
    "permission_check": "not_applicable",
    "sequential_fallback": true,
    "supported_modes": [],
    "tool": null,
    "transport": "sequential_text"
  },
  "tool_capability_requirements": [
    "file_read",
    "file_write",
    "repository_commands"
  ]
}
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. yesterday First seen · 44 lines · 20 tokens per session scan A e61c71d16524

Subscribe to this mod's changes

executor is an agent published in the GitHub repository cofin/flow (16 stars, last pushed 2d ago), licensed Apache-2.0. It adds 20 tokens to every session and 338 once invoked, about $0.0001 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.