context-optimizer

name	context-optimizer
version	1.2.0
description	Analyze skill content for optimal placement (Skill vs Passive Context vs Hybrid), compress markdown to pipe-delimited format (60-80% token reduction), and validate compliance against the decision framework. Passive context wins for what the model cannot know (post-cutoff APIs, repo gotchas); pre-trained knowledge belongs in progressive disclosure. Use when you ask "compress this skill", "Skill vs Passive Context placement", "reduce tokens". Do NOT use for gathering knowledge before a task (use context-gather).
license	MIT
user-invocable	true
allowed-tools	["view","bash","glob"]

Context Optimizer

Tooling suite for optimizing Claude Code context placement. Passive context (AGENTS.md, @imports) achieves 100% pass rates versus 53-79% for skills by eliminating decision points.

Triggers

• analyze skill placement - classify and validate content as Skill vs Passive Context
• compress markdown - reduce token count for context files
• optimize context - lower API costs and improve agent performance
• extract and index - split markdown into detail files with compact index
• audit always-on rules - eval-gated procedure for whether a rule earns its slot, and the doctrine behind it, in rule-audit-procedure.md and model-context-doctrine.md. Also the entry point when a new model ships. Requires a full rjmurillo/ai-agents checkout: the procedure runs this repo's eval harness and rule generator, neither of which ships in a plugin install. The doctrine and the instrument write-ups are readable anywhere; only the commands need the checkout

Process

1. Analyze: Run analyze_skill_placement.py to classify content
2. Compress: Run compress_markdown_content.py to reduce token counts
3. Validate: Run test_skill_passive_compliance.py to check compliance
4. Verify: Confirm output JSON contains expected classification and metrics

Verification

• Classification matches expected type (Skill/PassiveContext/Hybrid)
• Compression achieves target reduction (40-80% depending on level)
• Compliance validator returns exit code 0
• Output JSON is valid and contains all required fields

Scripts

Script	Purpose	Exit Codes
analyze_skill_placement.py	Classify content as Skill/PassiveContext/Hybrid	0=success, 1=error
compress_markdown_content.py	Compress markdown with token reduction metrics	0=success, 1=error, 2=config, 3=external
test_skill_passive_compliance.py	Validate compliance with decision framework	0=pass, 1=violations
extract_and_index.py	Extract sections into detail files with pipe-delimited index	0=success, 1=error, 2=config, 3=external
path_validation.py	Shared CWE-22 repo-root-anchored path validation	N/A (library module)

Prerequisites

Python 3.12+ with tiktoken for local token counting:

uv pip install -e ".[dev]"   # includes tiktoken
pip install tiktoken           # or install directly

tiktoken is an offline tokenizer (cl100k_base encoding) that approximates Claude tokenization. No API key is required for these scripts.

Decision Framework

The first question is not "skill or passive context." It is: does the model already know this?

Passive Context Earns Its Slot Only For What The Model Cannot Know

• Repo-specific gotchas (a gate that rejects one exact string, a hook that must not be bypassed)
• Local conventions that contradict the common default
• APIs newer than the training cutoff, which is exactly what the Vercel eval measured
• Routing tables, catalogs, and protocols specific to this repository

Keep Out Of Passive Context

• Generic engineering knowledge the model already has: SOLID, Clean Code, refactoring catalogs, testing pyramids. It does not earn an always-on slot without task-specific evidence that it changes behavior. It bills tokens on every edit, in every language, forever. The burden is on the content to prove it helps, not on the reader to prove it does not.
• Anything already stated in another always-on file. Duplicates drift apart, and then the agent spends reasoning reconciling them instead of doing the work.

Use Skills For

• Tool-based actions (file modification, API calls, git operations)
• User-triggered workflows (PR creation, issue management)
• Multi-step procedures (conflict resolution, session completion)
• Actions requiring validation (security scans, linting)
• Depth on knowledge the model partly has, loaded on demand

Hybrid Pattern

• Knowledge in passive context (routing, classification)
• Actions in skill (script execution, state changes)
• Example: pr-comment-responder is routed from the always-on AGENTS.md skill table, and its scripts stay in the skill

Why This Matters

Configuration	Pass Rate
Baseline (no docs)	53%
Skill (default)	53%
Skill + explicit instructions	79%
AGENTS.md passive context	100%

Skills create decision points where agents must choose whether to retrieve documentation. These introduce 4 failure modes: late retrieval, partial retrieval, integration failure, and instruction fragility. Passive context eliminates all four by being always-available.

Read That Table Honestly

The 53 to 100 percent result is real and it is narrow. Vercel's suite targeted Next.js 16 APIs chosen because they were absent from model training data. That is a knowledge-injection problem: an agent cannot retrieve what it does not know it is missing, so putting the docs in front of it wins.

It is not evidence that pre-trained knowledge belongs in passive context. Anthropic's Claude 5 context-engineering guidance points the other way for behavioral instruction, naming overconstraint as the failure mode after cutting more than 80 percent of a system prompt with no measurable coding-eval loss. Both results hold, because they answer different questions:

Content	Model already knows it	Where it goes
A post-cutoff framework API	No	Passive context
This repo's dash ban, its gates	No	Passive context
SOLID, Clean Code, refactoring	Yes	Progressive disclosure, or nowhere
Deep book material	Partly	Progressive disclosure

The pass-rate table has no cost column. Passive context is paid on every request, forever, whether or not the task needs it. This repository adopted the strategy in #1022 with a stated budget of Vercel's own 8KB figure; the always-on corpus later reached about 95KB on a .py edit. The enforced ceilings ratchet to measured size, so a passing budget gate is not evidence the corpus is small. Measure with scripts/validation/instruction_budget.py before adding always-on text, and prefer deleting a duplicate over compressing one.

References

• model-context-doctrine.md - What the current doctrine is, why Vercel and Shihipar do not conflict, per-model levers, and how to update when a new model ships. Read this before arguing about always-on content.
• rule-audit-procedure.md - Repeatable procedure for deciding whether an always-on rule earns its slot, including the eval commands and the decision table. Contributor-only: its commands invoke this repo's eval harness and rule generator
• rule-audit-instrument.md - What the eval can and cannot resolve, the noise floor, and the known instrument gotchas. Read before believing any number the eval prints
• rule-audit-evidence.md - Forensics behind the published table: which judge samples were lost, what recovering them changed, and what the loss does to the headline claim. Read before citing a cell
• rule-audit-parser-forensics.md - Repair history of the parser that produced the table: what more than twenty rounds of adversarial review found, and which fixes were themselves wrong. Read before writing a new instrument that parses judge output
• rule-audit-measurement-discipline.md - How the checks themselves went wrong: false negative controls, numbers read off the wrong population, and edits that silently deleted what they anchored on. Read before quoting a figure from a one-off command
• Vercel: AGENTS.md outperforms skills
• Analysis: .agents/analysis/vercel-passive-context-vs-skills-research.md
• Memory: passive-context-vs-skills-vercel-research
• vibe-engineering.md - 7-step agent interaction protocol for structured context optimization
• claude-code-productivity-patterns.md - Cost control, context management, and quality gates

Related

• Issue #1108: Build passive context tooling suite

Tool Details: Skill/Passive Content Analyzer

Script: scripts/analyze_skill_placement.py

Analyzes skill content and recommends Skill, Passive Context, or Hybrid placement.

The script reports shape, not admission. It cannot tell whether the model already knows the content, and that is the question the Decision Framework above turns on. Use it for size and duplication; the Decision Framework decides what earns an always-on slot.

Classification Logic:

• Tool Calls: Bash, Read, Write, Edit, gh, git, pwsh commands -> Skill
• Action Verbs: create, update, delete, execute, run -> Skill
• Reference Content: Tables, lists, code blocks -> Passive
• User Triggers: "when user", slash commands, explicit requests -> Skill

Usage:

# Analyze a skill directory (from repo root)
python3 .claude/skills/context-optimizer/scripts/analyze_skill_placement.py -p .claude/skills/github

# Analyze a specific SKILL.md
python3 .claude/skills/context-optimizer/scripts/analyze_skill_placement.py -p .claude/skills/github/SKILL.md

# Get detailed metrics
python3 .claude/skills/context-optimizer/scripts/analyze_skill_placement.py -p .claude/skills/github -d

Output:

{
  "classification": "Hybrid",
  "confidence": 85,
  "reasoning": "High tool execution (12 calls); High reference content ratio (0.75)",
  "recommendations": {
    "Passive": ["Routing Rules", 
      
  

Tool Details: Content Compression Utility

Script: scripts/compress_markdown_content.py

Compress markdown to pipe-delimited format achieving 60-80% token reduction while maintaining 100% information density.

Compression Techniques:

• Convert tables to pipe-delimited: |key: value|key2: value2|
• Extract headings to index: [Section] |item1 |item2
• Strip redundant words (the, a, an, is, are)
• Collapse whitespace and abbreviate common terms
• Preserve code blocks

Usage:

# Basic compression (JSON output to stdout)
python3 scripts/compress_markdown_content.py -i README.md -l medium

# Save to file with aggressive compression
python3 scripts/compress_markdown_content.py -i CRITICAL-CONTEXT.md -l aggressive -o compressed.txt

# With verbose metrics
python3 scripts/compress_markdown_content.py -i input.md -l medium -v

Compression Levels:

Level	Reduction	Techniques
Light	40-50%	Headers, tables, whitespace
Medium	50-60%	+ redundant words, tighter whitespace
Aggressive	60-80%	+ H3 compression, lists, abbreviations

Example (26 tokens -> 18 tokens, 31% reduction):

Before:

## Session Protocol

The session protocol has multiple phases:

1. Serena Activation - You must activate Serena

After:

[Session Protocol]
session protocol has multiple phases:
1. Serena Activation - activate Serena

Tool Details: Extract-and-Index Utility

Script: scripts/extract_and_index.py

Implements the Vercel extract-and-index pattern for 60-80% token reduction. Splits markdown by headings into detail files, generates a compact pipe-delimited index.

Usage:

# Extract sections and output JSON to stdout
python3 scripts/extract_and_index.py -i AGENTS.md -d .agents-details

# Write index to a file
python3 scripts/extract_and_index.py -i AGENTS.md -d .agents-details -o AGENTS-INDEX.md

# Custom reference path in index
python3 scripts/extract_and_index.py -i AGENTS.md -d .agents-details -r .agents-docs -o AGENTS-INDEX.md

Output Index Format (Vercel pattern):

[Architecture]
|Layered design with separation of concerns (see: .agents-details/architecture.md)
[Testing]
|80% coverage required for business logic (see: .agents-details/testing.md)

Works with CLAUDE.md @import mechanism. Reference via @AGENTS-INDEX.md.

Tool Details: Compliance Validator

Script: scripts/test_skill_passive_compliance.py

Validates content placement against the skill vs passive context decision framework.

6 Compliance Checks:

1. Skills contain actions (verbs, tool execution, scripts)
2. Passive context is knowledge-only (no action patterns)
3. CLAUDE.md under 200 lines (Anthropic recommendation)
4. @imported files exist and are readable
5. Skills have frontmatter (name and description)
6. No duplicate content between skills and passive context

Usage:

# Scan .claude directory (JSON output)
python3 scripts/test_skill_passive_compliance.py

# Scan specific directory with table output
python3 scripts/test_skill_passive_compliance.py --path .claude/skills/github --format table

Exit Codes: 0 = all passed, 1 = violations detected

Common Violations:

Violation	Fix
CLAUDE.md too long	Split into separate files, add @imports
Missing @import file	Create file or remove @import directive
Skill missing frontmatter	Add --- block with name: and description:
Skill has no actions	Add scripts or move to passive context
Passive has actions	Extract executable content to a skill
Duplicate content	Remove redundant content from skill or passive

Classification Examples

Clear Skill Classification

Input: GitHub skill with gh pr create, gh issue close commands

{"classification": "Skill", "confidence": 85, "reasoning": "High tool execution (8 calls); Many action verbs (12)"}

Clear Passive Classification

Input: Memory hierarchy reference, tables and lists, no commands

{"classification": "PassiveContext", "confidence": 80, "reasoning": "High reference content ratio (0.85)"}

Hybrid Classification

Input: PR comment responder with routing rules + script execution

{
  "classification": "Hybrid",
  "confidence": 65,
  "reasoning": "High reference content ratio (0.72); Some tool execution (4 calls)",
  "recommendations": {
    "Passive"  
      
  

Testing

python3 -m pytest tests/                                          # all tests
python3 -m pytest tests/test_skill_passive_compliance_test.py -v  # specific
python3 -m pytest tests/ --cov=scripts --cov-report=term-missing  # coverage

Coverage Summary:

Component	Tests	Key Areas
Compliance Validator	19/20 (95%)	Line count, @imports, frontmatter, duplicates, exit codes
Analyzer	Full	Tool calls, action verbs, classification logic, confidence scoring
Extract-and-Index	36	Slug generation, parsing, index format, 60%+ reduction targets
Compressor	Full	All levels, code block preservation, 40-80% reduction targets

Implementation Notes

• Language: Python 3.12+ per ADR-042 (PowerShell deprecated)
• Testing: pytest with comprehensive coverage
• Exit codes: ADR-035 standardization (0 = success, non-zero = failure)
• Type safety: Full type hints using dataclasses and typing module
• Cross-platform: pathlib for platform-independent path handling

Marketplace Value

• Automated optimization: Compress context without manual editing
• Quality gates: Enforce best practices in CI/CD
• Token savings: 60-80% reduction = lower API costs