feat(prompts): subagent fleet doctrine — evidence + git discipline

agent/prompt_builder.py

@@ -278,6 +278,28 @@ def _strip_yaml_frontmatter(content: str) -> str:
     "every assignee in a real profile (`hermes profile list`, or ask the user), "
     "and express dependencies via `parents=[...]` on `kanban_create`, not prose.\n"
     "\n"
+    "## Shared-checkout git discipline (non-negotiable)\n"
+    "\n"
+    "When a task requires working in a LIVE repository (not your kanban "
+    "workspace), other agents and humans may be in the same checkout AT THE "
+    "SAME TIME. Collisions here have caused real incidents (a worker's staged "
+    "file swept into another agent's commit; a branch cut from a moved HEAD):\n"
+    "- `git branch --show-current` and `git status` FIRST — never branch from "
+    "an unverified HEAD; another agent may have moved it or left the tree dirty.\n"
+    "- Isolate immediately: your own branch before any edit (`git checkout -b "
+    "<task-slug>`), or `git worktree add` for full isolation. One agent = one "
+    "branch = one working state.\n"
+    "- Stage explicit paths and commit immediately: `git add <paths> && git "
+    "commit`. NEVER leave work staged-but-uncommitted — a concurrent "
+    "committer's bare `git commit` sweeps the whole index and steals your "
+    "staged files into THEIR commit.\n"
+    "- Never `git commit -a`, never force-push a branch you don't own, never "
+    "resolve merge conflicts via the GitHub web UI — a conflict resolution is "
+    "a code change: do it locally and run the tests before pushing.\n"
+    "- When done, leave the shared checkout as you found it: original branch "
+    "restored, `git status --porcelain` empty. A dirty/non-main checkout can "
+    "silently break nightly automation that requires main.\n"
+    "\n"
     "## Do NOT\n"
     "\n"
     "- Do not shell out to `hermes kanban <verb>` for board operations. Use "

tests/tools/test_kanban_tools.py

@@ -1505,8 +1505,10 @@ def test_kanban_guidance_prompt_size_bounded(monkeypatch, tmp_path):
     The block absorbed the load-bearing worker/orchestrator reference
     details (workspace kinds, deliverable artifacts, created-card claims,
     profile discovery) when the standalone kanban-worker / kanban-orchestrator
-    skills were removed and folded into this always-injected guidance, so the
-    ceiling is sized to fit that content with a little headroom.
+    skills were removed and folded into this always-injected guidance, plus
+    the shared-checkout git discipline section added with the subagent fleet
+    doctrine, so the ceiling is sized to fit that content with a little
+    headroom.
     """
     monkeypatch.setenv("HERMES_KANBAN_TASK", "t_fake")
     home = tmp_path / ".hermes"
@@ -1516,7 +1518,7 @@ def test_kanban_guidance_prompt_size_bounded(monkeypatch, tmp_path):
     monkeypatch.setattr(_P, "home", lambda: tmp_path)
 
     from agent.prompt_builder import KANBAN_GUIDANCE
-    assert 1_500 < len(KANBAN_GUIDANCE) < 5_500, (
+    assert 1_500 < len(KANBAN_GUIDANCE) < 8_000, (
         f"KANBAN_GUIDANCE is {len(KANBAN_GUIDANCE)} chars — too short (missing?) or too long"
     )
 

tools/delegate_tool.py

@@ -696,6 +696,33 @@ def _build_child_system_prompt(
         "- What you found or accomplished\n"
         "- Any files you created or modified\n"
         "- Any issues encountered\n\n"
+        "## Honesty and evidence (non-negotiable)\n"
+        "Your summary is a SELF-REPORT the parent will independently verify before\n"
+        "trusting it. Make verification cheap and lying impossible:\n"
+        "- Every claim of completion must cite observable evidence: the command you\n"
+        "  ran and what it actually printed, the artifact path, URL, PR/issue number,\n"
+        "  or exit code. 'Tests pass' without the summary line is not evidence.\n"
+        "- Never report success you did not observe. Never invent output, counts,\n"
+        "  paths, or timestamps to fill a gap. 'I could not verify X because Y' is a\n"
+        "  valid, valued answer — fabricated certainty is not.\n"
+        "- If a step failed, quote the real error verbatim and stop there — the\n"
+        "  parent decides the next move, not your optimism.\n"
+        "- Operations with external side effects (pushes, PRs, deploys, writes to\n"
+        "  shared paths) require a verifiable handle in the summary (URL, id, sha).\n\n"
+        "## Git discipline in shared checkouts (non-negotiable)\n"
+        "Other agents and humans may be working in the same repository AT THE SAME\n"
+        "TIME. Before any git work in a repo you did not create for this task:\n"
+        "- Run `git branch --show-current` and `git status` FIRST — never branch from\n"
+        "  an unverified HEAD (another agent may have moved it).\n"
+        "- If you will write code, isolate yourself: `git worktree add <path> -b <branch>`\n"
+        "  or your own branch immediately. One agent = one branch = one working state.\n"
+        "- Stage only explicit paths and commit immediately: `git add <paths> && git commit`.\n"
+        "  NEVER leave files staged-but-uncommitted (a concurrent committer's `git commit`\n"
+        "  sweeps the whole index and steals your staged work into their commit).\n"
+        "- Never `git commit -a`, never resolve merge conflicts via the GitHub web UI\n"
+        "  (a resolution is a code change — do it locally and run the tests).\n"
+        "- When finished in a shared checkout, leave it as you found it: original\n"
+        "  branch restored, working tree clean (`git status --porcelain` empty).\n\n"
         "Important workspace rule: Never assume a repository lives at /workspace/... or any other container-style path unless the task/context explicitly gives that path. "
         "If no exact local path is provided, discover it first before issuing git/workdir-specific commands.\n\n"
         "Keep your final summary tight: lead with outcomes, prefer bullet "