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.
git clone --depth 1 https://github.com/markmhendrickson/foundationWrote 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/rules/markmhendrickson/foundation/dependency_installation)<a href="https://agentmods.dev/rules/markmhendrickson/foundation/dependency_installation"><img src="https://agentmods.dev/badge/rules/markmhendrickson/foundation/dependency_installation/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.
<a href="https://agentmods.dev/rules/markmhendrickson/foundation/dependency_installation"><img src="https://agentmods.dev/badge/rules/markmhendrickson/foundation/dependency_installation.svg" alt="Reviewed on agentmods" width="80" 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 5.1 | $0.00028 | $0.01024 |
| Opus 5.5 | $0.00011 | $0.00410 |
| Sonnet 5.5 | $0.00006 | $0.00205 |
| Haiku 4.5 | $0.00003 | $0.00102 |
Grade A, and why
dependency_installation 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 1mo 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 — 147 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Dependency Installation Rule
Ensures agents automatically install required dependencies when needed to fulfill prompts.
Rule
Always install required dependencies as needed to fulfill prompts.
When implementing features, fixing bugs, or making changes that require dependencies:
- Detect missing dependencies - Identify when code requires packages, tools, or libraries that are not installed
- Install automatically - Install dependencies without asking for permission
- Use appropriate package manager - Use the correct package manager for the project (npm, yarn, pip, etc.)
- Verify installation - Confirm dependencies are installed and accessible before proceeding
When This Applies
- When adding new imports that require packages not in
package.json,requirements.txt, or equivalent - When using tools or commands that require installation (e.g.,
npx,pip install) - When code references libraries that are not currently installed
- When running scripts that depend on external tools
- When setting up development environments
Agent Actions
1. Detect Missing Dependencies
Before implementing code that requires dependencies:
- Check if imports reference packages not in dependency files
- Verify tools/commands are available before use
- Identify missing runtime dependencies
2. Install Dependencies
Install using the appropriate method:
Node.js/TypeScript projects:
npm install <package-name>
# or for dev dependencies
npm install --save-dev <package-name>
Python projects:
pip install <package-name>
# or
pip install -r requirements.txt
Other package managers:
- Use the project's configured package manager
- Follow project conventions for dependency management
3. Update Dependency Files
After installing:
- Update
package.json,requirements.txt, or equivalent dependency files - Include version specifications when appropriate
- Separate dev dependencies from production dependencies
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.
- 1mo ago First seen · 147 lines · 28 tokens per session scan A b9aa251607ea
dependency_installation is a cursor rule published in the GitHub repository markmhendrickson/foundation (2 stars, last pushed 2mo ago), licensed MIT. It adds 28 tokens to every session and 1,024 once invoked, about $0.0001 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.
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