Add prompt-caching examples for fetch API #42

subtleGradient · 2025-11-11T23:52:24Z

Add prompt-caching examples for fetch API

Add comprehensive documentation in docs/prompt-caching.md
Add 4 separate example files in typescript/fetch/src/prompt-caching/:
- system-message-cache.ts: Cache on system message
- user-message-cache.ts: Cache on user message
- multi-message-cache.ts: Cache in multi-turn conversation
- no-cache-control.ts: Control scenario (no caching)
Add shared workspace with LARGE_SYSTEM_PROMPT constant
Add Bun monorepo structure with workspaces
Add Makefile for build orchestration
Add biome.jsonc for code quality

Run biome format on prompt-caching examples

Simplify examples section to link only to folder

Simplify fetch prompt-caching README to link to main docs

Rename prompt caching examples with anthropic prefix

subtleGradient · 2025-11-11T23:52:38Z

Add prompt-caching examples for AI SDK v5 #43 : 2 dependent PRs (#44 , #51 )
Add FileParserPlugin example for fetch API #50
Add prompt-caching examples for fetch API #42 👈 (View in Graphite)
Clean slate: Remove all content except LICENSE.md and .env.sample #41
main

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socket-security · 2025-11-11T23:52:50Z

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Diff	Package	Supply Chain Security	Vulnerability	Quality	Maintenance	License
	@types/bun@1.3.2
	typescript@5.9.3
	@biomejs/biome@1.9.4

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socket-security · 2025-11-11T23:52:52Z

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Copilot

Pull Request Overview

This PR adds comprehensive prompt caching examples for the fetch API, demonstrating Anthropic's prompt caching feature via OpenRouter. The PR includes documentation, example implementations, and build infrastructure with a Bun monorepo structure.

Adds 3 prompt-caching example files demonstrating system message caching, user message caching, and multi-message conversation caching
Creates shared workspace with reusable constants (LARGE_SYSTEM_PROMPT) and TypeScript types
Adds comprehensive documentation in docs/prompt-caching.md covering multiple providers
Sets up Bun monorepo with workspaces, Makefile orchestration, and Biome code quality tooling

Reviewed Changes

Copilot reviewed 17 out of 18 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
typescript/shared/tsconfig.json	TypeScript configuration for shared workspace with Bun types
typescript/shared/src/types.ts	Shared type definitions for chat completions, cache control, and usage metrics
typescript/shared/src/constants.ts	Large system prompt constant for cache testing and model identifiers
typescript/shared/package.json	Package configuration for shared workspace with exports
typescript/package.json	Root monorepo package with workspace definitions and scripts
typescript/fetch/tsconfig.json	TypeScript configuration for fetch examples workspace
typescript/fetch/src/prompt-caching/anthropic-user-message-cache.ts	Example demonstrating user message caching with cache_control
typescript/fetch/src/prompt-caching/anthropic-no-cache-control.ts	Control scenario example without cache_control markers
typescript/fetch/src/prompt-caching/anthropic-multi-message-cache.ts	Multi-turn conversation caching example
typescript/fetch/src/prompt-caching/README.md	Documentation for fetch API prompt caching examples
typescript/fetch/package.json	Fetch workspace package with example scripts
typescript/fetch/README.md	Overview of fetch examples workspace
typescript/README.md	TypeScript monorepo overview and documentation
docs/prompt-caching.md	Comprehensive prompt caching guide covering all providers
biome.jsonc	Code quality and formatting configuration
README.md	Repository root documentation and quick start guide
Makefile	Build orchestration for running examples
.gitignore	Git ignore patterns for dependencies and artifacts

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typescript/fetch/src/prompt-caching/anthropic-user-message-cache.ts

typescript/fetch/src/prompt-caching/anthropic-no-cache-control.ts

typescript/fetch/src/prompt-caching/anthropic-multi-message-cache.ts

typescript/fetch/src/prompt-caching/README.md

typescript/fetch/package.json

typescript/fetch/README.md

README.md

subtleGradient · 2025-11-12T23:41:05Z

docs/prompt-caching.md

@@ -0,0 +1,190 @@
+# Prompt Caching


TODO: link to https://openrouter.ai/docs/features/prompt-caching instead of duplicating the content here

louisgv · 2025-11-13T10:07:11Z

typescript/package.json

+    "@biomejs/biome": "^1.9.4",
+    "typescript": "^5.7.2"


freeze deps

louisgv · 2025-11-13T10:07:21Z

typescript/shared/package.json

+    "@types/bun": "latest",
+    "typescript": "^5.7.2"


use fixed deps

louisgv · 2025-11-13T10:07:53Z

typescript/shared/src/types.ts

can we pul these types from the SDK instead (?)

currently nothing we can just drop-in to do this; the types in the sdk have different casing for params and the ones with the correct casing aren't much better than adding as any;
planning on looking into this deeper in a separate PR

louisgv · 2025-11-13T10:08:17Z

typescript/fetch/src/prompt-caching/anthropic-user-message-cache.ts

+    // Use a large context document in the user message
+    const largeContext = `Here is a comprehensive TypeScript codebase to analyze:\n\n${LARGE_SYSTEM_PROMPT}`;
+
+    const requestBody = {


this shoudl satisfies something

currently nothing we can just drop-in to do this; planning on looking into this deeper in a separate PR

louisgv · 2025-11-13T10:09:53Z

typescript/fetch/run-examples.ts

+const examples = findExamples(srcDir);
+console.log(`Found ${examples.length} example(s)\n`);
+
+let failed = 0;


this bugs me a bit -- would prefer no let

planning to refactor this script in a separate PR

louisgv

Woud ensure deps are frozen

subtleGradient · 2025-11-13T14:47:53Z

Merge activity

Nov 13, 2:47 PM UTC: A user started a stack merge that includes this pull request via Graphite.
Nov 13, 2:48 PM UTC: Graphite rebased this pull request as part of a merge.
Nov 13, 2:50 PM UTC: Graphite couldn't merge this PR because it was not satisfying all requirements (PR does not have required approvals).

The base branch was changed.

- Add comprehensive documentation in docs/prompt-caching.md - Add 4 separate example files in typescript/fetch/src/prompt-caching/: - system-message-cache.ts: Cache on system message - user-message-cache.ts: Cache on user message - multi-message-cache.ts: Cache in multi-turn conversation - no-cache-control.ts: Control scenario (no caching) - Add shared workspace with LARGE_SYSTEM_PROMPT constant - Add Bun monorepo structure with workspaces - Add Makefile for build orchestration - Add biome.jsonc for code quality

Replace hardcoded filename list with run-examples.ts that auto-discovers all .ts files in src/ Benefits: - Add new example → automatically included in 'bun examples' - Rename example → no package.json update needed - Impossible for package.json to reference non-existent files Also fixes stale filenames (user-message-cache.ts → anthropic-user-message-cache.ts)

subtleGradient

will freeze deps and follow up with separate PRs for bringing stricter types to the fetch examples

subtleGradient · 2025-11-13T18:22:47Z

typescript/fetch/run-examples.ts

+const examples = findExamples(srcDir);
+console.log(`Found ${examples.length} example(s)\n`);
+
+let failed = 0;


planning to refactor this script in a separate PR

subtleGradient · 2025-11-13T18:23:31Z

typescript/fetch/src/prompt-caching/anthropic-user-message-cache.ts

+    // Use a large context document in the user message
+    const largeContext = `Here is a comprehensive TypeScript codebase to analyze:\n\n${LARGE_SYSTEM_PROMPT}`;
+
+    const requestBody = {


currently nothing we can just drop-in to do this; planning on looking into this deeper in a separate PR

subtleGradient · 2025-11-13T18:24:31Z

typescript/shared/src/types.ts

currently nothing we can just drop-in to do this; the types in the sdk have different casing for params and the ones with the correct casing aren't much better than adding as any;
planning on looking into this deeper in a separate PR

subtleGradient mentioned this pull request Nov 11, 2025

Clean slate: Remove all content except LICENSE.md and .env.sample #41

Merged

This was referenced Nov 11, 2025

Add prompt-caching examples for AI SDK v5 #43

Open

Add prompt-caching examples for Effect AI #44

Open

Add prompt-caching placeholder for OpenRouter SDK #45

Open

Add basic OpenRouter SDK example extracted from wrapper repo #46

Open

subtleGradient marked this pull request as ready for review November 11, 2025 23:53

Copilot AI review requested due to automatic review settings November 11, 2025 23:53

Copilot started reviewing on behalf of subtleGradient November 11, 2025 23:54 View session

Copilot finished reviewing on behalf of subtleGradient November 11, 2025 23:54

Copilot AI reviewed Nov 11, 2025

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subtleGradient commented Nov 12, 2025

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louisgv reviewed Nov 13, 2025

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louisgv approved these changes Nov 13, 2025

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louisgv previously approved these changes Nov 13, 2025

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subtleGradient changed the base branch from 01-clean-slate to graphite-base/42 November 13, 2025 14:48

subtleGradient changed the base branch from graphite-base/42 to main November 13, 2025 14:48

subtleGradient added 7 commits November 13, 2025 14:48

Run biome format on prompt-caching examples

e6c95f5

Simplify examples section to link only to folder

e25d9d3

Simplify fetch prompt-caching README to link to main docs

dfa3461

Rename prompt caching examples with anthropic prefix

f85e1cc

Remove filename references from docs to prevent sync issues

8be9df3

subtleGradient force-pushed the 02-prompt-caching-fetch branch from af129be to 8be9df3 Compare November 13, 2025 14:48

subtleGradient commented Nov 13, 2025

View reviewed changes

Add prompt-caching examples for fetch API #42

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