## What changed
- Add `ToolCallSource` to extension `ToolCall`s and propagate direct or Code Mode
invocation metadata, including the runtime cell and nested tool-call IDs.
- Add `ToolCall::response_byte_budget` so extension tools can bound direct-call
responses by the host truncation policy while allowing Code Mode responses up
to the tool's own limit.
- Share the skills extension's response-size limit between its `list` and `read`
tools.
## Testing
- Verify that Code Mode source metadata is preserved when core constructs an
extension tool call.
GitOrigin-RevId: b10aef01be30d35b67bee3af24a1a4175c9ee112
## What changed
Rename the token-budget configuration key and its Rust field from
`use_history_notes_history` to `use_history_notes_extension`. Update the config
schema, extension gating, explicit-setting detection, and tests to use the new
name consistently.
GitOrigin-RevId: b6a514e23f02095fcd1d35dc42eeb7394b800c77
## Why
Token-budget sessions need a way to recover prior conversation context and preserve working state across context-window transitions.
## What changed
- Add direct-model `history` tools for listing windows and items, reading items, and searching conversation contents.
- Add direct-model `notes` tools for listing, reading, searching, appending, and writing persistent notes.
- Route tool calls through the configured Codex backend with trusted session and agent context, bounded request arguments, and truncation-aware output handling.
- Expose the extension when `features.token_budget.use_history_notes_history` is enabled with an OpenAI provider and Codex backend authentication.
## Testing
- Cover tool registration, configuration changes, provider and authentication requirements, backend request context, encrypted output preservation, and request and response limits.
GitOrigin-RevId: 43b259f01014ba3f30803dd7cd5634942407a9bb