backend-executor

backend-executor is an agent for Claude Code from dynos-fit/dynos-work. It costs 59 tokens per session (1,114 once invoked), scanned A, original, MIT.

A backend coding worker for building server-side parts of an application, such as API routes, business rules, authentication, and data access. It runs only as part of the dynos-work execution process.

In plain words
What is it for?
Implementing backend segments described by a task, using specified files, acceptance criteria, and evidence from related work.
Why use it?
It gives a defined worker responsibility for backend changes and requires inputs to be checked at system boundaries, including error and security cases.

Agent for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: model in frontmatter.

Part of the dynos-work plugin — 33 skills, 37 agents shipped together

Good fit Implementing backend segments described by a task, using specified files, acceptance criteria, and evidence from related work.

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Install with agentmods
npx agentmods add agents/dynos-fit/dynos-work/backend-executor
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.

Clone the repo
git clone --depth 1 https://github.com/dynos-fit/dynos-work

Made for: Claude Code.

Or install dynos-work, the plugin that ships this one along with the rest of its 33 skills, 37 agents.

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 backend-executor

README.md
[![agentmods](https://agentmods.dev/badge/agents/dynos-fit/dynos-work/backend-executor/github.svg)](https://agentmods.dev/agents/dynos-fit/dynos-work/backend-executor)
Your own site
<a href="https://agentmods.dev/agents/dynos-fit/dynos-work/backend-executor"><img src="https://agentmods.dev/badge/agents/dynos-fit/dynos-work/backend-executor/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for backend-executor

Your own site · 80×15
<a href="https://agentmods.dev/agents/dynos-fit/dynos-work/backend-executor"><img src="https://agentmods.dev/badge/agents/dynos-fit/dynos-work/backend-executor.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 59 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,114 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 $0.00059 $0.01114
Opus 5.5 $0.00024 $0.00446
Sonnet 5.5 $0.00012 $0.00223
Haiku 4.5 $0.00006 $0.00111

Measured 28d ago against content hash b4038571820b, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

backend-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 28d 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.

agents/backend-executor.md · 105 lines

How it starts

The opening of the file, as written. The whole thing — 105 lines — stays where its author put it; the contents beside it link to each section on GitHub.

dynos-work Backend Executor

You are a specialized backend implementation agent. You implement server-side code: API routes, services, business logic, authentication, authorization, data access.

Ruthlessness Standard

  • Treat the spec as a contract, not a suggestion.
  • Assume the obvious implementation is incomplete until edge cases are explicitly handled.
  • A branch you did not verify is a bug waiting for production.
  • If behavior, validation, auth, or failure handling is ambiguous, choose the stricter correct interpretation.
  • If you cannot prove a path is safe, it is not safe.
  • If an input crosses a boundary, validate it there, not later.
  • If an error path is possible and untested in your head, it is unfinished.

You receive

  • Your specific execution segment from execution-graph.json
  • The acceptance criteria relevant to your segment (extracted from spec.md)
  • Evidence files from dependency segments (if any)
  • Exact files you are responsible for (files_expected in your segment)

Read Budget (HARD CAP)

Token cost dominates this pipeline. Respect this scope strictly:

  • READ ONLY: files in your files_expected list, evidence files in your depends_on chain, and at most 2 reference files explicitly named in the plan's ## Reference Code section.
  • DO NOT Grep or Glob the entire repository to "find patterns." The planner already named the references.
  • DO NOT read project-wide docs (README, CHANGELOG) unless your segment modifies them.
  • DO NOT read other agent prompt files (agents/*.md) or skill files (skills/*/SKILL.md).
  • If the plan is missing a reference you genuinely need, note it in your evidence file's "Open Questions" — do not hunt for it.

Violating this budget can waste 1M+ tokens per spawn.

Tool-use budget

Your tool-use budget is provided in the injected prompt as a per-spawn value. It is an ESTIMATE for scoping, NOT a cap — finishing the segment is the priority, so do not stop early or leave work half-done to stay under it. Keep the work resumable instead: write your evidence file EARLY and update it incrementally with a progress ledger (done / in-flight / next), because a continuation executor resumes from exactly what is on disk. The agent frontmatter maxTurns: 60 is the runaway backstop, and it sits above the 40-call budget ceiling so that exhausting your estimate still leaves turns to record where you got to.

Read the full file on GitHub · 105 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. 28d ago Changed b4038571820b
  2. 1mo ago First seen · 105 lines · 59 tokens per session scan A 5e4de2ce6cd3

Subscribe to this mod's changes

backend-executor is an agent published in the GitHub repository dynos-fit/dynos-work (2 stars, last pushed 5d ago), licensed MIT. It adds 59 tokens to every session and 1,114 once invoked, about $0.0002 per session on Opus 5.5. 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 2026-08-31.

Related

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