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ctxcap

naeha-s/ctxcap

Offline context-budget MCP server for AI coding agents.

GitHub stars
2
tools
4
transport
STDIO
last updated
Nov 13, 2026
View on GitHub

Tools

4 tools

Public tool metadata for what this MCP can expose to an agent.

measure_contextReturns the full JSON report for the current working directory

Returns the full JSON report for the current working directory

No parameter schema in public metadata yet.

context_budget_planReturns a deterministic ranked splice plan with safety classifications and preserve spans

Returns a deterministic ranked splice plan with safety classifications and preserve spans

No parameter schema in public metadata yet.

context_budget_verifyReports missed edits and preserve-span violations after applying a plan

Reports missed edits and preserve-span violations after applying a plan

No parameter schema in public metadata yet.

trim_to_budgetDeprecated alias for `context_budget_plan`; always returns `apply: false`

Deprecated alias for `context_budget_plan`; always returns `apply: false`

No parameter schema in public metadata yet.

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Readme

ctxcap

Offline token-budget linter for agent context files. It measures CLAUDE.md, AGENTS.md, prompts/**, and .cursor/rules/**, finds references that no longer resolve, and hands your agent a ranked, verifiable plan to get back under budget.

No config, API key, network, or telemetry. Node >= 20. Two runtime dependencies: fast-glob and gpt-tokenizer.

npx ctxcap --json

The loop

Context files get trimmed by agents badly: the agent rewrites the file from memory, drops the ## Never rules, hits the budget, and ships a worse file. ctxcap closes that loop with line ranges, safety flags, and verification.

npx ctxcap --plan --budget 40000              # ranked plan, JSON
npx ctxcap --plan --budget 40000 --apply      # splice atomically
npx ctxcap --verify <planId>                  # catch drift and violations

Three rules for the agent:

  1. Splice by startLine/endLine. Never rewrite a file from scratch.
  2. Never cut a span listed in preserve.
  3. If satisfiable is false, report minAchievable and stop.

Where plans live

View the full README on GitHub

Details

Repository
github.com/naeha-s/ctxcap
Website
github.com/Naeha-S/ctxcap
Package
ctxcap-mcp
Transport
STDIO
Registry
MCP registry, active