Pi v0.86.0

New Features

• Prompt cache warming — Keep valuable prompt caches alive during long tool runs and optionally while idle using cost-aware refreshes. See Cache Warming.
• Bug reporting — Report problems with /bug using redacted diagnostics, optional transcripts, or exported ZIP archives. See Reporting Bugs.
• Transcript-aware prompt and tool updates — Preserve instruction and tool changes across resume and branch navigation while retaining cached prefixes. See before_agent_start.
• Offline Radius model catalog — Select Radius models immediately, with cached and live catalogs overlaid when available. See Radius.
• Per-model compaction budgets — Configure reserved and recent-token budgets by model. See Per-model overrides.

Breaking Changes

• Changed inherited pi-ai provider stream inputs from Context to normalized TranscriptContext values. Custom providers must read system prompts and tool declarations from context.messages with getCurrentSystemPrompt() and getCurrentTools(). See Custom Streaming API.
• Restricted inherited ToolCall.arguments and ToolResultMessage.details to JSON-compatible values, changed ToolResultMessage into a conditional type, and made JsonValue arrays readonly.
• user_bash now fails closed: errors or invalid defined results abort the command without invoking later handlers or executing locally. Return undefined to continue propagation; otherwise return { operations } or { result } (#9068).

Added

• Added transcript-backed mid-conversation system prompt and tool changes so instruction and tool updates survive resume and branch navigation while preserving cached prefixes on supported models. See before_agent_start and Entry Types (#9548).
• Added inherited native deferred tool loading for Fireworks Messages models. Use ToolSearch or tool_search as the loader name for prompt-prefix deferral (#9323).
• Added click toggling for branch summaries, compaction summaries, and skill invocation entries.
• Added the public Radius model catalog for immediate and offline model selection, with cached and live gateway catalogs overlaid when available.
• Added ctx.modelRegistry.stream() and streamSimple() for extension model calls through configured providers with resolved authentication (#8964).
• Added per-model reserveTokens and keepRecentTokens settings through compaction.modelOverrides, with ordinary compaction settings as fallback (#8133).
• Added compat.allowedFallbackModels configuration for overriding or disabling Anthropic server-side fallback models (#9294).
• Added an unsubscribe function from pi.on() so extensions can drop event handlers. Handlers added or removed during a dispatch apply to later dispatches, not the current one (#8967).
• Exported extension hook event and result types that were previously omitted from the package entry points (#9642).
• Added /bug [description] to report a bug to the Pi developers. The report bundles environment, model, provider, extension, and settings metadata (secrets redacted), assistant message diagnostics from the session, optionally the session transcript, or a model-written summary of what went wrong instead. It is uploaded to Radius (no login required; attributed when logged in) or exported as a zip archive, and the report id is recorded in the session as a pi.bug-report entry. Crashes are recorded in ~/.pi/agent/crashes.json, announced once on the next start, and attached to the next report; unexplained errors and exhausted retries point at /bug once per session.
• Added cost-aware prompt-cache warming during long tool runs and optionally while idle, with configurable modes, model cache-lifetime metadata, /session diagnostics, transcript notices, and the cache_warming_decision extension event. See Cache Warming (#9668).

Changed

• Made --resume session results appear progressively, using file modification times to prioritize all-folder loading and cancelling outstanding transcript reads after selection.
• Reduced --continue startup time by checking candidate session headers in modification-time order and stopping after the newest matching session.
• Replaced the external native clipboard dependency with bundled asynchronous macOS, Windows, and X11 helpers while preserving platform command and OSC 52 fallbacks (#9163).
• Reduced inherited fuzzy search latency for long texts by using native substring search instead of scanning each character in JavaScript (#9267).
• Moved compaction, branch summarization, and retry spinners into the editor border alongside the working indicator. Custom editors use the same embedding opt-in for all status spinners.
• Enabled strict-prefer JSON-schema sampling by default for built-in read, bash, powershell, edit, and write tools, without requiring PI_EXPERIMENTAL. Extensions can re-register tool definitions with constrainedSampling: false.
• Formatted Bash and PowerShell tool durations of at least one minute as minutes and seconds, with hours when needed (#9628).
• Deferred the extension compiler and bundled virtual modules until a filesystem extension is loaded, reducing the baseline SDK import cost (#9540).

Fixed

• Fixed GitHub Copilot GPT models, including GPT-6 Astra, using the Chat Completions adapter instead of the required Responses adapter (#9253 by @petrroll).
• Fixed inherited DeepSeek V4.1 thinking levels on OpenRouter and OpenCode Go preserving provider effort metadata (#9485).
• Fixed inherited bodyless HTTP 400/413 errors from non-Cerebras providers being misclassified as context overflow (#9482).
• Fixed inherited Vercel AI Gateway replaying unsigned thinking as assistant text (#9676).
• Fixed inherited Google Generative AI and Vertex AI using unsupported thinking levels when reasoning is omitted or when model capabilities differ within a Gemini family (#9455).

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