* feat(core): add fork_turns to subagents
* fix(core): preserve nested agent context inheritance
* fix(core): isolate inherited subagent history
* refactor(core): scope fork_turns to fork agents
* test(core): cover zero-real-turns branch in selectForkHistory
Add a regression guard asserting selectForkHistory returns [] when a
numeric fork window finds no real user turns after the synthetic prefix
(e.g. only startup context present). This pins the
realUserTurnIndexes.length === 0 branch so a future refactor cannot
silently return the full history instead of an empty selection.
* docs(core): address fork_turns review feedback
- Explain the curated vs uncurated history split between the fork_turns
'all' and numeric paths in createForkSubagent.
- Document why includeCompressed is load-bearing in selectForkHistory.
- Gate the 'forks inherit ...' prose in the Writing-the-prompt section
behind isForkSubagentEnabled so non-interactive sessions no longer
advertise fork behavior, and lock it with description assertions.
* test(core): cover fork_turns 'all' and getHistoryForForkWindow fallback
Add two integration tests for prepareForkConfig fork-history selection:
- 'all' path: verify getHistoryShallow(true) sources the curated history
and selectForkHistory(history, 'all') seeds the fork with the full
history verbatim.
- numeric path: verify the getHistoryForForkWindow?.() ?? getHistory(true)
fallback still produces a correct bounded window (startup + latest real
turn) when getHistoryForForkWindow is unavailable.
* fix(core): use uncurated history for fork bounded-window fallback
The numeric fork_turns path falls back to geminiClient.getHistory(true)
when getHistoryForForkWindow is unavailable. Curated history coalesces
the leading startup reminder into the first real user turn, so
getStartupContextLength can no longer detect it as a pure prefix.
selectForkHistory then leaves the startup text embedded in the first
selected turn while the startupContext prefix is prepended separately,
duplicating startup context in the fork's initial messages.
Fall back to uncurated getHistory() instead, which keeps the startup
reminder as its own pure entry that selectForkHistory strips cleanly.
Update the fallback-path test to assert the uncurated call and document
why curated history is unsafe here.
---------
Co-authored-by: Claude <noreply@anthropic.com>
* docs(design): define default background subagents
* feat(core): improve subagent delegation defaults
* docs(core): cross-reference the three background-classification sites
Add pointer comments linking the core dispatch source of truth
(AgentTool.execute) and its two UI mirrors (web-shell
isBackgroundSubAgentToolCall, desktop detectBackgroundEvents) so the
replicated top-level-agent background heuristic is not changed in
isolation. Addresses PR review feedback.
* fix(core): align background classification for fork and named-teammate launches
Address review feedback on the background-classification rule so core dispatch
and the two UI classifiers stay consistent:
- core: exclude a name-without-active-team launch from the default-background
path so it stays foreground, matching both UI classifiers (which exclude
name). Previously such a launch was backgrounded by core but tracked as
foreground by the UIs.
- web-shell and desktop classifiers: exclude subagent_type "fork" from the
default-background heuristic, mirroring core's !isForkRequested guard. A
top-level fork request with an omitted flag runs foreground in core but was
classified as background by the UIs.
- add a core dispatch test asserting a working_dir launch with an omitted
run_in_background flag stays in the foreground.
* test: cover fork/background classification and precedence per review feedback
Address unresolved review threads on PR #7048:
- Add web-shell and desktop UI classifier tests asserting an omitted-flag
`subagent_type: "fork"` launch stays in the foreground, verifying the
documented `!isForkRequested` parity with core dispatch.
- Add a core AgentTool test asserting an explicit `run_in_background: false`
overrides a subagent config with `background: true`, locking in the
`run_in_background ?? config` precedence against a `||` regression.
- Harden the Explore read-only prompt: pipelines must not send data to a
network endpoint (no curl/wget/nc), closing the `cat file | curl`
exfiltration gap.
* fix(core): restore general no-unnecessary-files guard in general-purpose prompt
Address review feedback: the rewritten general-purpose prompt dropped the
broad guard against creating unrequested files, keeping only the
documentation-specific line. Restore a general 'do not create files unless
necessary' guard so speculative utility/config files are not created.
* test(desktop): cover named-teammate foreground guard in detectBackgroundEvents
Add a desktop tool-matching test asserting a top-level Agent with a
`name` set (named teammate) stays foreground and emits no
task_backgrounded event, mirroring the web-shell classifier's
named-teammate coverage and the existing fork-exclusion test.
* test(core): cover named-teammate foreground dispatch when flag omitted
Add a core-dispatch test asserting a top-level Agent launch with `name`
set and `run_in_background` omitted stays foreground when no team is
active, guarding the `this.params.name === undefined` exclusion in
backgroundRequested directly (previously only covered by the UI
classifiers).
---------
Co-authored-by: Claude <noreply@anthropic.com>
