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Burapa-J
Burapa-J

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How to Cut Claude Code & Cursor Token Costs by 40% and Enforce Evidence-First Verification (SKILL.md Playbook)

If you use Claude Code, Cursor, Windsurf, or GitHub Copilot daily on production repositories, you have almost certainly run into two expensive failure modes:

  1. The "Build Passed = Done" Illusion: Your coding agent compiles the project, sees exit 0, and confidently declares the bug fixed — without ever running a real behavioral reproducer, checking sibling callers, or proving the new test actually fails when the guard is removed.
  2. The 28k-Token Subagent Tax: Your agent spawns subagents for single-file edits (< 1,000 lines) or runs parallel builds against a single locked build directory (target/), burning 3x more tokens and stalling on file locks.

Over the past several months building high-reliability TypeScript monorepos, macOS apps, and Model Context Protocol (MCP) pipelines, I codified a strict set of SKILL.md playbooks that eliminate both problems.

Here is the exact architecture behind those playbooks — plus how to install both our Free B2B MCP Skills and our AI Engineering & Token Efficiency Pro Suite directly into Claude Code, Cursor, or Windsurf.

1. Evidence-First Engineering (devguard)

Most system prompts tell an LLM to "be careful and write tests." That fails under context pressure because the model optimizes for completing the turn.

Instead, an evidence-first SKILL.md enforces three non-negotiable rules:

Rule A: Capture Uncompressed Runtime Proof (agent-verify)

Token-saving shell wrappers and truncated terminal buffers hide subtle failures. Every verification check must write its full output and exit code to .verify/<name>.log:

mkdir -p .verify && npm test > .verify/unit-tests.log 2>&1; echo "exit=$?"
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The agent must read .verify/<name>.log directly and end every factual claim with a verifiable citation:

  • (read packages/ppe-guard/src/index.ts:411-431)
  • (ran: agent-verify unit-tests -- npm test -> exit 0)

Rule B: Mutation-Check Every New Test

A test that passes on the first try might be asserting the wrong code path. Before a test counts as proof, the agent must prove the test can fail by temporarily removing the guard or reverting the fix, watching the test fail for the exact expected reason, and restoring the fix.

Rule C: Pre-Mortem Table Before Writing Code

Before shipping any new feature, the agent must fill out a 4-column pre-mortem table covering concurrency, partial failure/rerun idempotency, upgrade/rollback, and data loss:

What Breaks When It Happens Design That Prevents It Test That Proves It
Double billing on retry Container restarts mid-batch KV-persisted ChargeLedger with idempotent event keys ppe-guard.test.ts (replay simulation)
Runaway failed-item compute Upstream API returns 5xx spike 35% cost-weighted circuit breaker after 8 items ppe-guard.test.ts (breaker threshold test)

2. The 28k-Token Rule (token-budget-architect)

Every time a coding agent spawns a subagent, bootstrapping the system prompt, tool schemas, and repo context costs roughly 28,000 tokens per turn.

To cut token consumption by 35%–45% without losing speed, route work using quantitative thresholds:

+-----------------------------------------------------------------------+
| Task Scope                           | Optimal Execution Route        |
+--------------------------------------+--------------------------------+
| Single-file edit (< 1,000 lines)     | MAIN_AGENT_DIRECT (0 overhead) |
| Known file:line review-fix round     | MAIN_AGENT_DIRECT              |
| Shared build lock (e.g. Cargo target)| MAIN_AGENT_DIRECT              |
| Reading >= 30,000 raw tokens         | CONSOLIDATED_BATCH_SUBAGENT    |
| (>= 3,500 lines across 2-3 modules)  | (Single-shot read-only scout)  |
+-----------------------------------------------------------------------+
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By pre-filtering files with 0-token bash/regex (grep / ast-grep) and dispatching at most 1–2 consolidated single-shot read-only subagents when reading >= 30,000 raw tokens, you completely eliminate multi-turn subagent ping-pong.

3. Ready-to-Install SKILL.md Playbooks on Agensi.io

We packaged our production SKILL.md workflows so they install into Claude Code, Cursor, Copilot, Windsurf, and 20+ coding agents in one click on Agensi.io:

Paid Engineering & FinOps Skills (Launch Week: 21%–36% Off)

  1. devguard — Evidence-First Engineering & Verification Workflow ($15 Launch Deal, reg. $19) — Playbooks for bug bisection, mutation-tested verification, pre-mortem tables, and .verify/ receipts.
  2. token-budget-architect — Subagent & Context Window Cost Optimizer ($11 Launch Deal, reg. $14) — Enforces the 28k-token subagent threshold, 0-token bash pre-filtering, and single-shot batch delegation.
  3. cloud-gpu-breakeven-auditor — AI Infrastructure & LLM FinOps Auditor ($19 Launch Deal, reg. $24) — Models Serverless API vs. Dedicated GPU (H100/A100/L40S) utilization breakeven points, KV-cache sizing, and tail-latency SLAs.
  4. swiss-minimal-ui-ledger — High-Craft Financial & Technical UI System ($15 Launch Deal, reg. $19) — Enforces tabular numeric discipline, hairlines, dark/light surface polarity, and WCAG AA contrast without generic SaaS bloat.

Best Value — 4-in-1 Pro Bundle ($49, Save 36%): Get all 4 engineering skills together in the AI Engineering & Token Efficiency Pro Suite.

4. Bonus: 5 Free B2B Intelligence MCP Skills (@apexsignal)

If you are building AI Sales, Recruiting, or GTM Agents using the Model Context Protocol (MCP), all 5 of our Free MCP Skills are now live on Agensi (@burapa) alongside our open-source @apexsignal B2B Intelligence MCP Suite (v1.1.0) (mcp.apify.com):

  1. B2B Hiring Intent & Lead Enrichment Pipeline (MCP) — Free (apexsignal/b2b-hiring-intent-lead-pipeline)
  2. B2B Domain Contact, DNS MX & Tech Stack Enricher (MCP) — Free (apexsignal/b2b-domain-contact-enricher)
  3. Tech Career & ATS Job Scraper - Greenhouse/Lever/Ashby (MCP) — Free (apexsignal/ats-career-job-listing-api)
  4. B2B Executive & Decision Maker Email Lead Finder (MCP) — Free (apexsignal/b2b-company-lead-finder)
  5. Bulk Corporate Email MX & Deliverability Verifier (MCP) — Free (apexsignal/bulk-email-mx-verifier)

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