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.
npx agentmods add skills/itallstartedwithaidea/agent-skills/subagent-driven-developmentnpx skills add itallstartedwithaidea/agent-skills --skill subagent-driven-developmentgit clone --depth 1 https://github.com/itallstartedwithaidea/agent-skillsWrote 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.
[](https://agentmods.dev/skills/itallstartedwithaidea/agent-skills/subagent-driven-development)<a href="https://agentmods.dev/skills/itallstartedwithaidea/agent-skills/subagent-driven-development"><img src="https://agentmods.dev/badge/skills/itallstartedwithaidea/agent-skills/subagent-driven-development.svg" alt="Measured on agentmods" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00038 | $0.01262 |
| Opus 5 | $0.00019 | $0.00631 |
| Sonnet 5 | $0.00008 | $0.00252 |
| Haiku 4.5 | $0.00004 | $0.00126 |
Grade A, and why
subagent-driven-development 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 2d 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.
How it starts
The opening of the file, as written. The whole thing — 131 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Subagent-Driven Development
Part of Agent Skills™ by googleadsagent.ai™
Description
Subagent-Driven Development dispatches each discrete task to a fresh subagent with a clean context window, then subjects the output to a two-stage review before merging. The orchestrating agent decomposes work into atomic units, writes precise specifications for each, and spawns isolated subagents that cannot pollute each other's context or carry forward stale assumptions.
Context window contamination is the silent killer of agent code quality. As a conversation grows, early instructions fade, variable names blur, and the agent begins referencing code that has since been refactored. By giving each task a fresh subagent, every implementation starts from a clean slate with only the relevant specification and referenced files. The result is consistently high-quality output regardless of session length.
The two-stage review process catches defects at different abstraction levels. Stage 1 verifies spec compliance: does the output do what was asked? Stage 2 evaluates code quality: is it well-structured, tested, and maintainable? Only code that passes both gates is accepted into the codebase.
Use When
- A task can be decomposed into 3+ independent subtasks
- The conversation context has grown large enough to risk coherence loss
- Multiple files or modules must be modified in parallel
- You need best-of-N attempts for a complex implementation
- Quality gates must be enforced consistently across all outputs
- The user requests parallel or isolated task execution
How It Works
graph TD
A[Orchestrator: Decompose Task] --> B[Write Spec for Subtask 1]
A --> C[Write Spec for Subtask 2]
A --> D[Write Spec for Subtask N]
B --> E[Spawn Subagent 1]
C --> F[Spawn Subagent 2]
D --> G[Spawn Subagent N]
E --> H[Stage 1: Spec Compliance Review]
F --> H
G --> H
H --> I{Passes?}
I -->|No| J[Return to Subagent with Feedback]
J --> H
I -->|Yes| K[Stage 2: Code Quality Review]
K --> L{Passes?}
L -->|No| J
L -->|Yes| M[Merge to Main Branch]
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.
- 2d ago First seen · 131 lines · 38 tokens per session scan A 8623a62a78cb
subagent-driven-development is a skill published in the GitHub repository itallstartedwithaidea/agent-skills (36 stars, last pushed 4mo ago), licensed MIT. It adds 38 tokens to every session and 1,262 once invoked, about $0.0002 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 2026-09-03.
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