989 pages for note.
Titles and paths first, then pages whose text carries it. Each row opens that page as this site last read it.
overview
Claude Developer Platform · in the page
models/fable-5-1/overview
…prompt" icon="text" href="https://platform.claude.com/docs/en/release-notes/system-prompts/claude-fable-5-1"> The system prompt Claude Fable 5.1 uses on claude.ai and the Claude apps. </Card>…
migration-guide
Claude Developer Platform · in the page
models/fable-5-2/migration-guide
…includes model IDs, breaking changes, and migration checklists. --- <Note> This guide covers migrating [Messages API](https://platform.claude.com/docs/en/build-with-claude/working-with-messages) co…
overview
Claude Developer Platform · in the page
models/fable-5-2/overview
…prompt" icon="text" href="https://platform.claude.com/docs/en/release-notes/system-prompts/claude-fable-5-2"> The system prompt Claude Fable 5.2 uses on claude.ai and the Claude apps. </Card>…
overview
Claude Developer Platform · in the page
models/fable-5/overview
…prompt" icon="text" href="https://platform.claude.com/docs/en/release-notes/system-prompts/overview#claude-fable-5"> The system prompt Claude Fable 5 uses on claude.ai and the Claude apps. </Car…
overview
Claude Developer Platform · in the page
models/haiku-4-5/overview
…prompt" icon="text" href="https://platform.claude.com/docs/en/release-notes/system-prompts/overview#claude-haiku-4-5"> The system prompt Claude Haiku 4.5 uses on claude.ai and the Claude apps. <…
migration-guide
Claude Developer Platform · in the page
models/haiku-5-5/migration-guide
…ors, thinking changes, and a checklist for each starting model. --- <Note> This guide covers migrating [Messages API](https://platform.claude.com/docs/en/build-with-claude/working-with-messages) co…
overview
Claude Developer Platform · in the page
models/haiku-5-5/overview
…prompt" icon="text" href="https://platform.claude.com/docs/en/release-notes/system-prompts/claude-haiku-5-5"> The system prompt Claude Haiku 5.5 uses on claude.ai and the Claude apps. </Card>…
overview
Claude Developer Platform · in the page
models/opus-4-5/overview
…prompt" icon="text" href="https://platform.claude.com/docs/en/release-notes/system-prompts/overview#claude-opus-4-5"> The system prompt Claude Opus 4.5 uses on claude.ai and the Claude apps. </C…
overview
Claude Developer Platform · in the page
models/opus-4-6/overview
…prompt" icon="text" href="https://platform.claude.com/docs/en/release-notes/system-prompts/overview#claude-opus-4-6"> The system prompt Claude Opus 4.6 uses on claude.ai and the Claude apps. </C…
overview
Claude Developer Platform · in the page
models/opus-4-7/overview
…prompt" icon="text" href="https://platform.claude.com/docs/en/release-notes/system-prompts/overview#claude-opus-4-7"> The system prompt Claude Opus 4.7 uses on claude.ai and the Claude apps. </C…
overview
Claude Developer Platform · in the page
models/opus-4-8/overview
…prompt" icon="text" href="https://platform.claude.com/docs/en/release-notes/system-prompts/overview#claude-opus-4-8"> The system prompt Claude Opus 4.8 uses on claude.ai and the Claude apps. </C…
migration-guide
Claude Developer Platform · in the page
models/opus-5-5/migration-guide
…cks in every response, and a checklist for each starting model. --- <Note> This guide covers migrating [Messages API](https://platform.claude.com/docs/en/build-with-claude/working-with-messages) co…
overview
Claude Developer Platform · in the page
models/opus-5-5/overview
…prompt" icon="text" href="https://platform.claude.com/docs/en/release-notes/system-prompts/claude-opus-5-5"> The system prompt Claude Opus 5.5 uses on claude.ai and the Claude apps. </Card> <…
whats-new-opus-5-5
Claude Developer Platform · in the page
models/opus-5-5/whats-new-opus-5-5
…s/en/build-with-claude/preserved-thinking) and the migration guide’s [note on thinking blocks](https://platform.claude.com/docs/en/models/opus-5-5/migration-guide#thinking-blocks). ### Some computer…
overview
Claude Developer Platform · in the page
models/opus-5/overview
…prompt" icon="text" href="https://platform.claude.com/docs/en/release-notes/system-prompts/overview#claude-opus-5"> The system prompt Claude Opus 5 uses on claude.ai and the Claude apps. </Card>…
overview
Claude Developer Platform · in the page
models/sonnet-4-5/overview
…prompt" icon="text" href="https://platform.claude.com/docs/en/release-notes/system-prompts/overview#claude-sonnet-4-5"> The system prompt Claude Sonnet 4.5 uses on claude.ai and the Claude apps.…
overview
Claude Developer Platform · in the page
models/sonnet-4-6/overview
…prompt" icon="text" href="https://platform.claude.com/docs/en/release-notes/system-prompts/overview#claude-sonnet-4-6"> The system prompt Claude Sonnet 4.6 uses on claude.ai and the Claude apps.…
migration-guide
Claude Developer Platform · in the page
models/sonnet-5-5/migration-guide
…on-guide#migration-checklist) lists every change by starting model. <Note> This guide covers migrating [Messages API](https://platform.claude.com/docs/en/build-with-claude/working-with-messages) co…
overview
Claude Developer Platform · in the page
models/sonnet-5-5/overview
…prompt" icon="text" href="https://platform.claude.com/docs/en/release-notes/system-prompts/claude-sonnet-5-5"> The system prompt Claude Sonnet 5.5 uses on claude.ai and the Claude apps. </Card>…
whats-new-sonnet-5-5
Claude Developer Platform · in the page
models/sonnet-5-5/whats-new-sonnet-5-5
…turn. A progress-update block you send back gives the model the full note it wrote, not the summary. If your requests don’t use tools, the response contains only text, as with `disabled` on Claude So…
overview
Claude Developer Platform · in the page
models/sonnet-5/overview
…prompt" icon="text" href="https://platform.claude.com/docs/en/release-notes/system-prompts/claude-sonnet-5"> The system prompt Claude Sonnet 5 uses on claude.ai and the Claude apps. </Card> <…
develop-tests
Claude Developer Platform · in the page
test-and-evaluate/develop-tests
…: Insurance details, payment records, etc. - Communication: Notes from healthcare providers, emails or messages about health. <response>{model_output}</response> Output…
handle-streaming-refusals
Claude Developer Platform · in the page
test-and-evaluate/strengthen-guardrails/handle-streaming-refusals
…ails` arrives on the `message_delta` event alongside `stop_reason`. <Note> A `refusal` response from streaming classifiers includes a `stop_details` object with a `category` and a human-readable `e…
increase-consistency
Claude Developer Platform · in the page
test-and-evaluate/strengthen-guardrails/increase-consistency
…} ] } ``` </Accordion> ## Prefill Claude’s response <Note> Prefilling is not supported on Claude 4.6 and later models and [Claude Mythos Preview](https://anthropic.com/glasswing…
mitigate-jailbreaks
Claude Developer Platform · in the page
test-and-evaluate/strengthen-guardrails/mitigate-jailbreaks
…them and that your screening and confirmation steps catch the rest. <Note> If you’re using the [computer use tool](https://platform.claude.com/docs/en/agents-and-tools/tool-use/computer-use-too…
reduce-hallucinations
Claude Developer Platform · in the page
test-and-evaluate/strengthen-guardrails/reduce-hallucinations
…information from provided documents and not its general knowledge. <Note> Remember, although these techniques significantly reduce hallucinations, they don’t eliminate them entirely. Always valida…
reduce-latency
Claude Developer Platform · in the page
test-and-evaluate/strengthen-guardrails/reduce-latency
…lying infrastructure supporting the model and point of interaction. <Note> It’s always better to first engineer a prompt that works well without model or prompt constraints, and then try latency re…
reduce-prompt-leak
Claude Developer Platform · in the page
test-and-evaluate/strengthen-guardrails/reduce-prompt-leak
…n reemphasize those instructions by prefilling the `Assistant` turn. (Note: prefilling is not supported on Claude 4.6 and later models and [Claude Mythos Preview](https://anthropic.com/glasswing).) <…
Set up Claude Code for your organization
Claude Code CLI · in the page
admin-setup
…ks to the section below and to the reference page for that area. > [!NOTE] > > SSO, SCIM provisioning, and seat assignment are configured at the Claude account level. See the [Claude Enterprise Admin…
Escalate hard decisions with the advisor tool
Claude Code CLI · in the page
advisor
…advisor model that Claude consults at key moments during a task. > [!NOTE] > > The advisor tool is experimental and requires the Anthropic API or [Claude Platform on AWS](https://code.claude.com/docs…
How the agent loop works
Claude Code CLI · in the page
agent-sdk/agent-loop
…s need no separate Claude Code install. See the [quickstart's install note](https://code.claude.com/docs/en/agent-sdk/quickstart.md) for the installs that do. When you start an agent, the SDK runs th…
Use Claude Code features in the SDK
Claude Code CLI · in the page
agent-sdk/claude-code-features
…type === "success") { console.log(message.result); } } ``` > [!NOTE] > > Skills must be created as filesystem artifacts (`.claude/skills/<name>/SKILL.md`). The SDK does not have a programmatic…
Configure your agent
Claude Code CLI · in the page
agent-sdk/configuration
…odel="claude-fable-5", fallback_model="claude-opus-5", ) ``` > [!NOTE] > > The [Messages API](https://platform.claude.com/docs/en/api/messages) request parameters `temperature`, `top_p`, and `max…
Give Claude custom tools
Claude Code CLI · in the page
agent-sdk/custom-tools
…and Claude receives its file path as text instead. | Field | Type | Notes | | :- | :- | :- | | `type` | `"image"` | | | `data` | `string` | Base64-encoded bytes. Raw base64 only, no `data:image/...;…
Examples
Claude Code CLI · in the page
agent-sdk/examples
…e Cookbook's Agent SDK series is a sequence of recipes, each a Python notebook, that progresses from a simple research agent to sophisticated multi-agent systems. Each notebook builds on the previous…
Rewind file changes with checkpointing
Claude Code CLI · in the page
agent-sdk/file-checkpointing
…/code.claude.com/docs/en/tools-reference.md#edit-tool-behavior), and [NotebookEdit](https://code.claude.com/docs/en/tools-reference.md#notebookedit-tool-behavior) tools during an agent session, allowi…
Intercept and control agent behavior with hooks
Claude Code CLI · in the page
agent-sdk/hooks
…a `PostToolUse` callback can also return `classifierContext`, a short note about the tool call's result for the [auto mode](https://code.claude.com/docs/en/permission-modes.md#eliminate-prompts-with-a…
Hosting the Agent SDK
Claude Code CLI · in the page
agent-sdk/hosting
…CLI needs no separate Node.js install. See the [quickstart's install note](https://code.claude.com/docs/en/agent-sdk/quickstart.md) for the installs that need a separate native Claude Code install.…
Connect to external tools with MCP
Claude Code CLI · in the page
agent-sdk/mcp
…nect over HTTP, or execute directly within your SDK application. > [!NOTE] > > This page covers MCP configuration for the Agent SDK. To add MCP servers to the Claude Code CLI so they load in every pr…
Migrate to Claude Agent SDK
Claude Code CLI · in the page
agent-sdk/migration-guide
…ti-tenant systems where local customizations should not leak in. > [!NOTE] > > Python SDK 0.1.59 and earlier treated an empty list the same as omitting the option, so upgrade before relying on `setti…
Modifying system prompts
Claude Code CLI · in the page
agent-sdk/modifying-system-prompts
…tyle": "Explanatory"}'` or a path to a settings file that sets it. **Note for SDK users:** Output styles are loaded when you include `settingSources: ['user']` or `settingSources: ['project']` (TypeS…
Observability with OpenTelemetry
Claude Code CLI · in the page
agent-sdk/observability
…ge](https://code.claude.com/docs/en/agent-sdk/cost-tracking.md). > [!NOTE] > > For the Claude API or Managed Agents, see [OpenTelemetry for the Claude API](https://platform.claude.com/docs/en/manage-…
Agent SDK overview
Claude Code CLI · in the page
agent-sdk/overview
…our first agent, one that finds and fixes bugs in existing code. > [!NOTE] > > Unless previously approved, Anthropic does not allow third party developers to offer claude.ai login or rate limits for…
Configure permissions
Claude Code CLI · in the page
agent-sdk/permissions
…le everything else at runtime. ## How permissions are evaluated > [!NOTE] > > If you load a plugin that contains a [mod](https://code.claude.com/docs/en/plugins/mods/overview.md), see [where a mod's…
Plugins in the SDK
Claude Code CLI · in the page
agent-sdk/plugins
…ile system paths (for example, `"/home/user/plugins/my-plugin"`) > [!NOTE] > > The path should point to the plugin's root directory: the parent of `skills/`, `agents/`, `hooks/`, `commands/`, or `.cl…
Agent SDK reference - Python
Claude Code CLI · in the page
agent-sdk/python
…when the next action depends on Claude's response. ## Functions > [!NOTE] > > Signature blocks and bare `async for` / `async with` fragments on this page are illustrative. To run them, wrap the body…
Quickstart
Claude Code CLI · in the page
agent-sdk/quickstart
…or, run `Set-ExecutionPolicy -Scope Process RemoteSigned` first. > [!NOTE] > > Both the TypeScript and Python SDKs bundle a native Claude Code binary, so most installs need no separate Claude Code in…
Securely deploying AI agents
Claude Code CLI · in the page
agent-sdk/secure-deployment
…ween security strength, performance, and operational complexity. > [!NOTE] > > In all of these configurations, Claude Code (or your Agent SDK application) runs inside the isolation boundary (the sand…
Persist sessions to external storage
Claude Code CLI · in the page
agent-sdk/session-storage
…emory fake, a unique key prefix, or a new test database. ## Behavior notes ### Dual-write architecture The Claude Code subprocess always writes each batch of transcript entries to local disk first,…
Work with sessions
Claude Code CLI · in the page
agent-sdk/sessions
…from an interruption, or branch off to try a different approach. > [!NOTE] > > Sessions persist the **conversation**, not the filesystem. To snapshot and revert file changes the agent made, use [file…