fix(prompts): hoist ToolSearch activation to top of system prompt

Smoke-7: be-dev-1 hit "Edit exists but is not enabled in this context."
Claude Code v2.1.69+ defers built-in tools (Edit, Write, Read, etc.)
behind a ToolSearch call. Weak models (minimax-m2.7) skip soft
directives buried in the briefing.

Also: 4 role prompts (developer, cell_pm, main_pm, board) claimed
"no ToolSearch needed" — a lie that compounds the problem. The
manifest registers MCP tools; built-in tools are still deferred.

Fix: compose_prompt now prepends a tool-load directive layer as the
FIRST block in the system prompt. It names the exact ToolSearch call
the role needs:
- developer/documenter: Read, Bash, Grep, Glob, Task, TodoWrite, Edit, Write
- qa/pm/board: Read, Bash, Grep, Glob, Task, TodoWrite (no Edit/Write)

The directive includes the failure mode it prevents so the model
understands what skipping the call causes.

Updated role-prompt lines that lied about ToolSearch.

7 new tests pin: directive is the first block; developer/documenter
get Edit/Write; qa/pm don't; failure-mode message is present.

tests/unit/agents/test_tool_load_directive_layer.py

@@ -0,0 +1,95 @@
+"""Smoke-7: system prompt opens with a ToolSearch directive that activates
+deferred built-in tools (Edit, Write, Read, ...).
+
+Original bug: be-dev-1 called Edit and got "Edit exists but is not enabled
+in this context" because Claude Code v2.1.69+ defers built-in tools behind
+a ToolSearch call. The role prompts said "no ToolSearch needed" — a lie
+for built-in tools — so weak models skipped the activation step.
+
+Fix: compose_prompt now prepends a tool-load directive layer that names
+the exact ToolSearch call for the role. It's the highest-priority block in
+the system prompt so even weak models follow it.
+"""
+
+from __future__ import annotations
+
+from roboco.agents.factories._base import compose_prompt
+from roboco.models import AgentRole, Team
+
+
+def _composed_prompt_for(role: AgentRole, team: Team | None = None) -> str:
+    """Compose the prompt for a role and team."""
+    return compose_prompt(role, team, agent_slug="test-agent")
+
+
+def test_developer_prompt_starts_with_tool_load_directive() -> None:
+    """Developer system prompt begins with the ToolSearch activation block."""
+    prompt = _composed_prompt_for(AgentRole.DEVELOPER, Team.BACKEND)
+    assert prompt.startswith("# FIRST ACTION REQUIRED"), (
+        f"Developer prompt must lead with the tool-load directive. "
+        f"Got first 80 chars: {prompt[:80]!r}"
+    )
+
+
+def test_developer_directive_names_edit_and_write() -> None:
+    """Developer ToolSearch call lists Edit + Write (the smoke-7 wedge)."""
+    prompt = _composed_prompt_for(AgentRole.DEVELOPER, Team.BACKEND)
+    assert 'ToolSearch(query="select:' in prompt
+    # Find the ToolSearch line
+    line = next(line for line in prompt.splitlines() if "ToolSearch(query=" in line)
+    assert "Edit" in line, f"Developer ToolSearch missing Edit: {line!r}"
+    assert "Write" in line
+
+
+def test_documenter_directive_names_edit_and_write() -> None:
+    """Documenter needs Edit/Write too — they author docs."""
+    prompt = _composed_prompt_for(AgentRole.DOCUMENTER, Team.BACKEND)
+    line = next(line for line in prompt.splitlines() if "ToolSearch(query=" in line)
+    assert "Edit" in line
+    assert "Write" in line
+
+
+def _tool_list_from_directive(prompt: str) -> list[str]:
+    """Extract the comma-separated tool list from the ToolSearch call."""
+    line = next(line for line in prompt.splitlines() if "ToolSearch(query=" in line)
+    # `ToolSearch(query="select:Read,Bash,...")` — pull out the names.
+    start = line.find("select:") + len("select:")
+    end = line.find('"', start)
+    return line[start:end].split(",")
+
+
+def test_qa_directive_excludes_edit_and_write() -> None:
+    """QA reads but doesn't author — directive must NOT activate Edit/Write."""
+    tools = _tool_list_from_directive(_composed_prompt_for(AgentRole.QA, Team.BACKEND))
+    assert "Edit" not in tools, f"QA must not activate Edit: tools={tools}"
+    assert "Write" not in tools
+    assert "Read" in tools
+    assert "Bash" in tools
+
+
+def test_pm_directives_exclude_edit_and_write() -> None:
+    """PMs coordinate; they don't author code. No Edit/Write activation."""
+    for role in (AgentRole.MAIN_PM, AgentRole.CELL_PM):
+        tools = _tool_list_from_directive(_composed_prompt_for(role))
+        assert "Edit" not in tools, f"{role.value} must not activate Edit: {tools}"
+        assert "Write" not in tools
+
+
+def test_directive_explains_why_it_matters() -> None:
+    """The block must mention 'Edit exists but is not enabled' so the agent
+    understands what skipping the call causes."""
+    prompt = _composed_prompt_for(AgentRole.DEVELOPER, Team.BACKEND)
+    assert "Edit exists but is not enabled" in prompt
+
+
+def test_directive_is_first_layer_before_lifecycle() -> None:
+    """First Action block precedes the lifecycle and base layers."""
+    prompt = _composed_prompt_for(AgentRole.DEVELOPER, Team.BACKEND)
+    first_idx = prompt.find("# FIRST ACTION REQUIRED")
+    lifecycle_idx = prompt.find("Lifecycle")
+    base_idx = prompt.find("RoboCo Agent — Base")
+    assert first_idx == 0
+    if lifecycle_idx > -1:
+        assert first_idx < lifecycle_idx
+    if base_idx > -1:
+        assert first_idx < base_idx