15 pages for onblock.

Beta Claude Developer Platform · in the page api/beta …cache control breakpoint at this content block. - `BetaCompactionBlockParam object` A compaction block containing summary of previous context. Users should round-trip these bl… Messages Claude Developer Platform · in the page api/beta/messages …cache control breakpoint at this content block. - `BetaCompactionBlockParam object` A compaction block containing summary of previous context. Users should round-trip these bl… Batches Claude Developer Platform · in the page api/beta/messages/batches …e control breakpoint at this content block. - `BetaCompactionBlockParam object` A compaction block containing summary of previous context. Users should round-trip… Create a Message Batch Claude Developer Platform · in the page api/beta/messages/batches/create …e control breakpoint at this content block. - `BetaCompactionBlockParam object` A compaction block containing summary of previous context. Users should round-trip… Retrieve Message Batch results Claude Developer Platform · in the page api/beta/messages/batches/results …ner_upload - `file_id: string` - `BetaCompactionBlock object` A compaction block returned when autocompact is triggered. When content is None, it indi… Count tokens in a Message Claude Developer Platform · in the page api/beta/messages/count_tokens …cache control breakpoint at this content block. - `BetaCompactionBlockParam object` A compaction block containing summary of previous context. Users should round-trip these bl… Create a Message Claude Developer Platform · in the page api/beta/messages/create …cache control breakpoint at this content block. - `BetaCompactionBlockParam object` A compaction block containing summary of previous context. Users should round-trip these bl… sent_count = len(messages sent in the compaction request) Claude Developer Platform · in the page build-with-claude/compaction …tVariant.ContentBlock.AsAny().(type) { case anthropic.BetaCompactionBlock: fmt.Println("Compaction started...") case anthropic.BetaTextBlock: fmt.Println("Text response started...")… compaction-threshold Claude Developer Platform · in the page build-with-claude/compaction-threshold …tVariant.ContentBlock.AsAny().(type) { case anthropic.BetaCompactionBlock: fmt.Println("Compaction started...") case anthropic.BetaTextBlock: fmt.Println("Text response started...")… mid-conversation-system-messages Claude Developer Platform · in the page build-with-claude/mid-conversation-system-messages …ent = new( [ new BetaRequestToolAdditionBlock { Tool = new BetaToolChangeToolDefinitionParam {… Connect to external tools with MCP Claude Code CLI · in the page agent-sdk/mcp …-turn wait, before the init message is sent: * Set [`MCP_CONNECTION_NONBLOCKING`](/docs/en/env-vars) to `0` to block on the whole connection batch. Claude Code caps that wait at 5 seconds by default.… Environment variables Claude Code CLI · in the page env-vars …| | `CLAUDE_CODE_NONBLOCKING_STDOUT` | Set to `1` to write terminal output through a second non-blocking file descriptor, so… Automate actions with hooks Claude Code CLI · in the page hooks-guide …the deny `reason` appears in the chat as a warning line. Set `continueOnBlock: true` on the hook to instead return the `reason` to Claude as the tool error, so it can adjust and continue. Before v2.1.… Connect Claude Code to tools via MCP Claude Code CLI · in the page mcp …r servers connect in the background by default; set [`MCP_CONNECTION_NONBLOCKING=0`](/docs/en/env-vars) to make startup wait for them too. ## Use MCP prompts as commands MCP servers can expose promp… Week 20 · May 11–15, 2026 Claude Code CLI · in the page whats-new/2026-w20 …path placeholders never need quoting</div> <div>New <code>continueOnBlock</code> config option for <code>PostToolUse</code> hooks feeds the hook's rejection reason back to Claude and continues the…