docs: add adoption playbooks

README.md

@@ -99,6 +99,12 @@ echo "prompt body" | tokenometer - --model claude-sonnet-4-6
 
 Run `tokenometer --help` for the full flag list and the current set of known model ids (63 across 5 providers).
 
+## Adoption playbooks
+
+Use [`docs/ADOPTION.md`](docs/ADOPTION.md) for copy-paste integration paths:
+GitHub Actions cost gates, VS Code/Cursor rollout, MCP clients, LangChain,
+Vercel AI SDK, OpenAI SDK, Anthropic SDK, and a PR cost-regression case study.
+
 ## Five-line use
 
 ### 1. Compare formats for a single prompt (offline, no API key)

docs/ADOPTION.md

@@ -0,0 +1,143 @@
+# Tokenometer Adoption Playbooks
+
+Tokenometer is useful when token cost needs to be visible before prompts reach
+production. Pick the surface that matches the workflow: CLI for local checks,
+GitHub Action for PR guardrails, VS Code/Cursor for editor feedback, MCP for
+agent clients, and the library packages for app code.
+
+## GitHub Actions: Block Prompt-Cost Regressions
+
+```yaml
+name: prompt-cost
+
+on:
+  pull_request:
+    paths:
+      - "prompts/**"
+      - "src/**/*.prompt.*"
+
+jobs:
+  tokenometer:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+      - uses: faraa2m/tokenometer/packages/action@v1
+        with:
+          paths: prompts/**/*.md,src/**/*.prompt.ts
+          models: claude-sonnet-4-6,gpt-4o,gemini-2.5-pro
+          formats: markdown,json,yaml
+          budget: "0.25"
+          top-n-files: 10
+```
+
+Use this when prompt changes are reviewed like source code. The action posts a
+sticky PR comment with per-file deltas and fails the check when the total
+increase crosses the configured budget.
+
+## VS Code and Cursor
+
+```text
+ext install faraa2m.tokenometer-vscode
+```
+
+Recommended team defaults:
+
+```json
+{
+  "tokenometer.model": "claude-sonnet-4-6",
+  "tokenometer.format": "markdown",
+  "tokenometer.warnOnCostAbove": 0.05
+}
+```
+
+This gives prompt authors live token and USD feedback before CI runs.
+
+## MCP Clients
+
+```json
+{
+  "mcpServers": {
+    "tokenometer": {
+      "command": "npx",
+      "args": ["@tokenometer/mcp"]
+    }
+  }
+}
+```
+
+Use the MCP server when Claude Code, Cursor, or another agent client needs a
+real cost estimate instead of guessing from a rough token heuristic.
+
+## LangChain
+
+```ts
+import { tokenize } from "@tokenometer/core";
+
+export async function pricePrompt(prompt: string) {
+  return tokenize({
+    prompt,
+    modelId: "gpt-4o",
+    format: "text",
+  });
+}
+```
+
+Call this before a chain step that expands context, retrieves documents, or
+generates long summaries. Store the result next to trace metadata so cost can be
+reviewed with latency and quality.
+
+## Vercel AI SDK
+
+```ts
+import { tokenize } from "@tokenometer/core";
+
+export async function POST(req: Request) {
+  const { prompt } = await req.json();
+  const cost = tokenize({
+    prompt,
+    modelId: "gpt-4o",
+    format: "text",
+  });
+
+  if (cost.inputCost > 0.1) {
+    return Response.json({ error: "Prompt exceeds cost budget" }, { status: 400 });
+  }
+
+  // Continue with streamText/generateText after the budget gate.
+}
+```
+
+Use this pattern for user-generated prompts where a single request can become a
+large bill.
+
+## OpenAI and Anthropic SDK Guardrails
+
+```ts
+import { tokenize } from "@tokenometer/core";
+
+const prompt = "Summarize the attached support ticket history.";
+const cost = await tokenize({ prompt, modelId: "claude-sonnet-4-6", format: "text" });
+
+if (cost.inputCost > 0.05) {
+  throw new Error(`Prompt budget exceeded: $${cost.inputCost.toFixed(4)}`);
+}
+```
+
+Put the check immediately before the provider call. For production systems,
+record the estimate, selected model, prompt hash, and request id in logs.
+
+## Case Study: PR Cost Regression
+
+A team keeps support-agent prompts in `prompts/support/*.md`. A pull request
+adds several examples to improve tone, but the prompt cost doubles for every
+support ticket. Tokenometer catches the delta in CI before merge:
+
+1. The GitHub Action compares the PR branch against the base branch.
+2. The sticky comment shows which prompt file caused the increase.
+3. The check fails because the configured `budget` is exceeded.
+4. The author moves rare examples into retrieval data instead of the base
+   prompt, preserving quality without permanently increasing every call.
+
+This is the core operating model: prompt cost becomes a reviewable code change.