context-mode

name context-mode description Use context-mode tools (ctx_execute, ctx_execute_file) instead of Bash/cat when processing large outputs. Triggers: "analyze logs", "summarize output", "process data", "parse JSON", "filter results", "extract errors", "check build output", "analyze dependencies", "process API response", "large file analysis", "page snapshot", "browser snapshot", "DOM structure", "inspect page", "accessibility tree", "Playwright snapshot", "run tests", "test output", "coverage report", "git log", "recent commits", "diff between branches", "list containers", "pod status", "disk usage", "fetch docs", "API reference", "index documentation", "call API", "check response", "query results", "find TODOs", "count lines", "codebase statistics", "security audit", "outdated packages", "dependency tree", "cloud resources", "CI/CD output". Also triggers on ANY MCP tool output that may exceed 20 lines. Subagent routing is handled automatically via PreToolUse hook. Context Mode: Default for All Large Output MANDATORY RULE <context_mode_logic> <mandatory_rule> Default to context-mode for ALL commands. Only use Bash for guaranteed-small-output operations. </mandatory_rule> </context_mode_logic> Bash whitelist (safe to run directly): File mutations : mkdir , mv , cp , rm , touch , chmod Git writes : git add , git commit , git push , git checkout , git branch , git merge Navigation : cd , pwd , which Process control : kill , pkill Package management : npm install , npm publish , pip install Simple output : echo , printf Everything else → ctx_execute or ctx_execute_file . Any command that reads, queries, fetches, lists, logs, tests, builds, diffs, inspects, or calls an external service. This includes ALL CLIs (gh, aws, kubectl, docker, terraform, wrangler, fly, heroku, gcloud, etc.) — there are thousands and we cannot list them all. When uncertain, use context-mode. Every KB of unnecessary context reduces the quality and speed of the entire session. Decision Tree About to run a command / read a file / call an API? │ ├── Command is on the Bash whitelist (file mutations, git writes, navigation, echo)? │ └── Use Bash │ ├── Output MIGHT be large or you're UNSURE? │ └── Use context-mode ctx_execute or ctx_execute_file │ ├── Fetching web documentation or HTML page? │ └── Use ctx_fetch_and_index → ctx_search │ ├── Using Playwright (navigate, snapshot, console, network)? │ └── ALWAYS use filename parameter to save to file, then: │ browser_snapshot(filename) → ctx_index(path) or ctx_execute_file(path) │ browser_console_messages(filename) → ctx_execute_file(path) │ browser_network_requests(filename) → ctx_execute_file(path) │ ⚠ browser_navigate returns a snapshot automatically — ignore it, │ use browser_snapshot(filename) for any inspection. │ ⚠ Playwright MCP uses a SINGLE browser instance — NOT parallel-safe. │ For parallel browser ops, use agent-browser via execute instead. │ ├── Using agent-browser (parallel-safe browser automation)? │ └── Run via execute (shell) — each call gets its own subprocess: │ execute("agent-browser open example.com && agent-browser snapshot -i -c") │ ✓ Supports sessions for isolated browser instances │ ✓ Safe for parallel subagent execution │ ✓ Lightweight accessibility tree with ref-based interaction │ ├── Processing output from another MCP tool (Context7, GitHub API, etc.)? │ ├── Output already in context from a previous tool call? │ │ └── Use it directly. Do NOT re-index with ctx_index(content: ...). │ ├── Need to search the output multiple times? │ │ └── Save to file via ctx_execute, then ctx_index(path) → ctx_search │ └── One-shot extraction? │ └── Save to file via ctx_execute, then ctx_execute_file(path) │ └── Reading a file to analyze/summarize (not edit)? └── Use ctx_execute_file (file loads into FILE_CONTENT, not context) When to Use Each Tool Situation Tool Example Hit an API endpoint ctx_execute fetch('http://localhost:3000/api/orders') Run CLI that returns data ctx_execute gh pr list , aws s3 ls , kubectl get pods Run tests ctx_execute npm test , pytest , go test ./... Git operations ctx_execute git log --oneline -50 , git diff HEAD~5 Docker/K8s inspection ctx_execute docker stats --no-stream , kubectl describe pod Read a log file ctx_execute_file Parse access.log, error.log, build output Read a data file ctx_execute_file Analyze CSV, JSON, YAML, XML Read source code to analyze ctx_execute_file Count functions, find patterns, extract metrics Fetch web docs ctx_fetch_and_index Index React/Next.js/Zod docs, then search Playwright snapshot browser_snapshot(filename) → ctx_index(path) → ctx_search Save to file, index server-side, query Playwright snapshot (one-shot) browser_snapshot(filename) → ctx_execute_file(path) Save to file, extract in sandbox Playwright console/network browser_*(filename) → ctx_execute_file(path) Save to file, analyze in sandbox MCP output (already in context) Use directly Don't re-index — it's already loaded MCP output (need multi-query) ctx_execute to save → ctx_index(path) → ctx_search Save to file first, index server-side Wipe indexed KB content ctx_purge(confirm: true) Permanently deletes all indexed content Automatic Triggers Use context-mode for ANY of these, without being asked: API debugging : "hit this endpoint", "call the API", "check the response", "find the bug in the response" Log analysis : "check the logs", "what errors", "read access.log", "debug the 500s" Test runs : "run the tests", "check if tests pass", "test suite output" Git history : "show recent commits", "git log", "what changed", "diff between branches" Data inspection : "look at the CSV", "parse the JSON", "analyze the config" Infrastructure : "list containers", "check pods", "S3 buckets", "show running services" Dependency audit : "check dependencies", "outdated packages", "security audit" Build output : "build the project", "check for warnings", "compile errors" Code metrics : "count lines", "find TODOs", "function count", "analyze codebase" Web docs lookup : "look up the docs", "check the API reference", "find examples" Language Selection Situation Language Why HTTP/API calls, JSON javascript Native fetch, JSON.parse, async/await Data analysis, CSV, stats python csv, statistics, collections, re Shell commands with pipes shell grep, awk, jq, native tools File pattern matching shell find, wc, sort, uniq Search Query Strategy BM25 uses OR semantics — results matching more terms rank higher automatically Use 2-4 specific technical terms per query Always use source parameter when multiple docs are indexed to avoid cross-source contamination Partial match works: source: "Node" matches "Node.js v22 CHANGELOG" Always use queries array — batch ALL search questions in ONE call: ctx_search(queries: ["transform pipe", "refine superRefine", "coerce codec"], source: "Zod") NEVER make multiple separate ctx_search() calls — put all queries in one array External Documentation Always use ctx_fetch_and_index for external docs — NEVER cat or ctx_execute with local paths for packages you don't own For GitHub-hosted projects, use the raw URL: https://raw.githubusercontent.com/org/repo/main/CHANGELOG.md After indexing, use the source parameter in search to scope results to that specific document Critical Rules Always console.log/print your findings. stdout is all that enters context. No output = wasted call. Write analysis code, not just data dumps. Don't console.log(JSON.stringify(data)) — analyze first, print findings. Be specific in output. Print bug details with IDs, line numbers, exact values — not just counts. For files you need to EDIT : Use the normal Read tool. context-mode is for analysis, not editing. For Bash whitelist commands only : Use Bash for file mutations, git writes, navigation, process control, package install, and echo. Everything else goes through context-mode. Never use ctx_index(content: large_data) . Use ctx_index(path: ...) to read files server-side. The content parameter sends data through context as a tool parameter — use it only for small inline text. Always use filename parameter on Playwright tools ( browser_snapshot , browser_console_messages , browser_network_requests ). Without it, the full output enters context. Don't re-index data already in context. If an MCP tool returned data in a previous response, it's already loaded — use it directly or save to file first. Sandboxed Data Workflow <sandboxed_data_workflow> <critical_rule> When using tools that support saving to a file: ALWAYS use the 'filename' parameter. NEVER return large raw datasets directly to context. </critical_rule> LargeDataTool(filename: "path") → mcp__context-mode__ctx_index(path: "path") → ctx_search() </sandboxed_data_workflow> This is the universal pattern for context preservation regardless of the source tool (Playwright, GitHub API, AWS CLI, etc.). Examples Debug an API endpoint const resp = await fetch ( 'http://localhost:3000/api/orders' ); const { orders } = await resp. json (); const bugs = []; const negQty = orders. filter ( o => o. quantity < 0 ); if (negQty. length ) bugs. push ( `Negative qty: ${negQty.map(o => o.id).join( ', ' )} ` ); const nullFields = orders. filter ( o => !o. product || !o. customer ); if (nullFields. length ) bugs. push ( `Null fields: ${nullFields.map(o => o.id).join( ', ' )} ` ); console . log ( ` ${orders.length} orders, ${bugs.length} bugs found:` ); bugs. forEach ( b => console . log ( `- ${b} ` )); Analyze test output npm test 2>&1 echo "EXIT=$?" Check GitHub PRs gh pr list --json number,title,state,reviewDecision --jq '.[] | "\(.number) [\(.state)] \(.title) — \(.reviewDecision // "no review")"' Read and analyze a large file # FILE_CONTENT is pre-loaded by ctx_execute_file import json data = json.loads(FILE_CONTENT) print ( f"Records: { len (data)} " ) # ... analyze and print findings Browser & Playwright Integration When a task involves Playwright snapshots, screenshots, or page inspection, ALWAYS route through file → sandbox. Playwright browser_snapshot returns 10K–135K tokens of accessibility tree data. Calling it without filename dumps all of that into context. Passing the output to ctx_index(content: ...) sends it into context a SECOND time as a parameter. Both are wrong. The key insight : browser_snapshot has a filename parameter that saves to file instead of returning to context. ctx_index has a path parameter that reads files server-side. ctx_execute_file processes files in a sandbox. None of these touch context. Workflow A: Snapshot → File → Index → Search (multiple queries) Step 1: browser_snapshot(filename: "/tmp/playwright-snapshot.md") → saves to file, returns ~50B confirmation (NOT 135K tokens) Step 2: ctx_index(path: "/tmp/playwright-snapshot.md", source: "Playwright snapshot") → reads file SERVER-SIDE, indexes into FTS5, returns ~80B confirmation Step 3: ctx_search(queries: ["login form email password"], source: "Playwright") → returns only matching chunks (~300B) Total context: ~430B instead of 270K tokens. Real 99% savings. Workflow B: Snapshot → File → Execute File (one-shot extraction) Step 1: browser_snapshot(filename: "/tmp/playwright-snapshot.md") → saves to file, returns ~50B confirmation Step 2: ctx_execute_file(path: "/tmp/playwright-snapshot.md", language: "javascript", code: " const links = [...FILE_CONTENT.matchAll(/- link \"([^\"]+)\"/g)].map(m => m[1]); const buttons = [...FILE_CONTENT.matchAll(/- button \"([^\"]+)\"/g)].map(m => m[1]); const inputs = [...FILE_CONTENT.matchAll(/- textbox|- checkbox|- radio/g)]; console.log('Links:', links.length, '| Buttons:', buttons.length, '| Inputs:', inputs.length); console.log('Navigation:', links.slice(0, 10).join(', ')); ") → processes in sandbox, returns ~200B summary Total context: ~250B instead of 135K tokens. Workflow C: Console & Network (save to file if large) browser_console_messages(level: "error", filename: "/tmp/console.md") → ctx_execute_file(path: "/tmp/console.md", ...) or ctx_index(path: "/tmp/console.md", ...) browser_network_requests(includeStatic: false, filename: "/tmp/network.md") → ctx_execute_file(path: "/tmp/network.md", ...) or ctx_index(path: "/tmp/network.md", ...) CRITICAL: Why filename + path is mandatory | Approach | Context cost | Correct? |