# Pi: session-affinity config breaking change, dynamic tool loading, Fable 5 xhigh/max

> Removes the `openai-responses` `sendSessionIdHeader` flag — replace `sendSessionIdHeader: false` with `sessionAffinityFormat: "openai-nosession"` (breaking). Adds cache-friendly dynamic tool loading, a Ctrl+X copy shortcut, native xhigh/max thinking for Claude Fable 5, and toolChoice support.

| | |
|---|---|
| **Tool** | Pi |
| **Version** | v0.80.7 |
| **Kind** | release |
| **Published** | 2026-07-14 |
| **Observed** | 2026-08-21 |
| **Significance** | 4/5 |
| **Breaking** | yes |
| **Categories** | breaking, feature, api-change, fix, model-support |

## What changed


**Breaking**
- Removed `compat.sendSessionIdHeader` from `models.json`; session affinity now set via `compat.sessionAffinityFormat` (`"openai"`, `"openai-nosession"`, or `"openrouter"`) — migrate `sendSessionIdHeader: false` to `sessionAffinityFormat: "openai-nosession"` (#6496)

**New features**
- Extensions can add tools during execution while supported Anthropic and OpenAI Responses models preserve prompt-cache prefixes
- `Ctrl+X` copies the last assistant message, or selected message in `/tree`
- Inherited native `xhigh` and `max` thinking levels for Claude Fable 5 across generated provider catalogs (#6490)
- Inherited `toolChoice` support for OpenAI and Codex Responses, including required and named tool selection (#6588)

**Fixes**
- Inherited OpenRouter context windows now use top provider's actual context length (#6481)
- OpenRouter OpenAI-compatible session IDs now use `x-session-id` header (#6496)
- `/login amazon-bedrock` now prompts for and saves an API key; ambient AWS creds keep SigV4 (#6532)
- Cloudflare Workers AI / AI Gateway auth uses ambient account and gateway IDs (#6292)
- Legacy terminal decoding for `Alt+,`/`Alt+.` fixed (#6523)
- GitHub Copilot `mai-code-1-flash-picker` routes via `/responses` (#6544)
- Branch summaries work with ambient-auth providers (#6595); Bedrock surfaces unhandled stop reasons (#6598)
- System prompt cache invalidation fixed by dropping the date from the default prompt (#6621)


## Sources

- [github_release](https://github.com/earendil-works/pi/releases/tag/v0.80.7) — retrieved 2026-08-21


## Community

_No curated reactions recorded. Facts and community takes are kept in separate layers
and never blended._

---
Canonical: https://changelogs.info/pi/v0-80-7
Entity: https://changelogs.info/pi
Event ID: `evt_2026-07-14_pi_v0-80-7`
Licence: event synthesis © changelogs.info, CC BY 4.0. Linked sources belong to their vendors.