feat(templates): Session templates for code-first seeding (#505)

Code-heavy sessions improve over time. File-heavy sessions degrade.
Session templates seed new sessions with successful tool call patterns
to establish feedback loops early.

## What
- tools/session_templates.py — task type classification (60% threshold),
  template extraction from SQLite sessions, storage, injection, CLI
- tests/tools/test_session_templates.py — 17 tests

## Task types
CODE, FILE, RESEARCH, MIXED — classified by tool call frequency.

## CLI
python -m tools.session_templates list
python -m tools.session_templates create <session_id> --name my-template
python -m tools.session_templates delete <name>

Closes #329.

tests/tools/test_session_templates.py

@@ -0,0 +1,188 @@
+"""Tests for session templates (code-first seeding)."""
+
+import json
+import tempfile
+from pathlib import Path
+from unittest.mock import patch
+
+import pytest
+
+from tools.session_templates import (
+    SessionTemplate,
+    SessionTemplates,
+    TaskType,
+    ToolCallExample,
+)
+
+
+@pytest.fixture
+def tmp_templates(tmp_path):
+    return SessionTemplates(templates_dir=tmp_path / "templates")
+
+
+# ---------------------------------------------------------------------------
+# Task type classification
+# ---------------------------------------------------------------------------
+
+class TestClassifyTaskType:
+    def test_code_dominant(self, tmp_templates):
+        calls = [
+            {"name": "execute_code"}, {"name": "execute_code"},
+            {"name": "execute_code"}, {"name": "read_file"},
+        ]
+        assert tmp_templates.classify_task_type(calls) == TaskType.CODE
+
+    def test_file_dominant(self, tmp_templates):
+        calls = [
+            {"name": "read_file"}, {"name": "write_file"},
+            {"name": "patch"}, {"name": "read_file"},
+            {"name": "execute_code"},
+        ]
+        assert tmp_templates.classify_task_type(calls) == TaskType.FILE
+
+    def test_research_dominant(self, tmp_templates):
+        calls = [
+            {"name": "web_search"}, {"name": "web_fetch"},
+            {"name": "web_search"}, {"name": "read_file"},
+        ]
+        assert tmp_templates.classify_task_type(calls) == TaskType.RESEARCH
+
+    def test_mixed_no_dominant(self, tmp_templates):
+        calls = [
+            {"name": "execute_code"}, {"name": "read_file"},
+            {"name": "web_search"},
+        ]
+        assert tmp_templates.classify_task_type(calls) == TaskType.MIXED
+
+    def test_empty_returns_mixed(self, tmp_templates):
+        assert tmp_templates.classify_task_type([]) == TaskType.MIXED
+
+    def test_threshold_is_60_percent(self, tmp_templates):
+        # 59% code (5/9) should be MIXED
+        calls = [{"name": "execute_code"}] * 5 + [{"name": "read_file"}] * 4
+        assert tmp_templates.classify_task_type(calls) == TaskType.MIXED
+
+        # 60% code (6/10) should be CODE
+        calls = [{"name": "execute_code"}] * 6 + [{"name": "read_file"}] * 4
+        assert tmp_templates.classify_task_type(calls) == TaskType.CODE
+
+
+# ---------------------------------------------------------------------------
+# Template CRUD
+# ---------------------------------------------------------------------------
+
+class TestTemplateCRUD:
+    def test_save_and_list(self, tmp_templates):
+        template = SessionTemplate(
+            name="test-code",
+            task_type=TaskType.CODE,
+            examples=[
+                ToolCallExample(tool_name="execute_code", args={"code": "print('hi')"}, success=True),
+            ],
+            created_at="2026-01-01T00:00:00Z",
+        )
+        tmp_templates.save_template(template)
+
+        templates = tmp_templates.list_templates()
+        assert len(templates) == 1
+        assert templates[0].name == "test-code"
+        assert templates[0].task_type == TaskType.CODE
+
+    def test_list_filter_by_type(self, tmp_templates):
+        tmp_templates.save_template(SessionTemplate(name="t1", task_type=TaskType.CODE, examples=[]))
+        tmp_templates.save_template(SessionTemplate(name="t2", task_type=TaskType.FILE, examples=[]))
+
+        code_templates = tmp_templates.list_templates(TaskType.CODE)
+        assert len(code_templates) == 1
+        assert code_templates[0].name == "t1"
+
+    def test_delete(self, tmp_templates):
+        tmp_templates.save_template(SessionTemplate(name="delete-me", task_type=TaskType.CODE, examples=[]))
+        assert tmp_templates.delete_template("delete-me") is True
+        assert len(tmp_templates.list_templates()) == 0
+
+    def test_delete_nonexistent(self, tmp_templates):
+        assert tmp_templates.delete_template("nope") is False
+
+    def test_get_template_returns_best(self, tmp_templates):
+        tmp_templates.save_template(SessionTemplate(
+            name="low-usage", task_type=TaskType.CODE, examples=[], usage_count=1,
+        ))
+        tmp_templates.save_template(SessionTemplate(
+            name="high-usage", task_type=TaskType.CODE, examples=[], usage_count=5,
+        ))
+        best = tmp_templates.get_template(TaskType.CODE)
+        assert best.name == "high-usage"
+
+    def test_get_template_returns_none_if_empty(self, tmp_templates):
+        assert tmp_templates.get_template(TaskType.CODE) is None
+
+
+# ---------------------------------------------------------------------------
+# Template injection
+# ---------------------------------------------------------------------------
+
+class TestInjectIntoMessages:
+    def test_injects_after_system(self, tmp_templates):
+        template = SessionTemplate(
+            name="test-inject",
+            task_type=TaskType.CODE,
+            examples=[
+                ToolCallExample(
+                    tool_name="execute_code",
+                    args={"code": "x=1"},
+                    result_preview="1",
+                    success=True,
+                ),
+            ],
+        )
+        messages = [
+            {"role": "system", "content": "You are Timmy."},
+            {"role": "user", "content": "Hello"},
+        ]
+        result = tmp_templates.inject_into_messages(template, messages)
+
+        # Should have: system, template system note, assistant tool call, tool result, user
+        assert len(result) == 5
+        assert result[0]["role"] == "system"
+        assert "Session Template" in result[1]["content"]
+        assert result[2]["role"] == "assistant"
+        assert result[3]["role"] == "tool"
+        assert result[4]["role"] == "user"
+
+    def test_skips_failed_examples(self, tmp_templates):
+        template = SessionTemplate(
+            name="test-fail",
+            task_type=TaskType.CODE,
+            examples=[
+                ToolCallExample(tool_name="execute_code", args={}, success=False),
+                ToolCallExample(tool_name="read_file", args={"path": "x"}, success=True),
+            ],
+        )
+        messages = [{"role": "system", "content": "sys"}]
+        result = tmp_templates.inject_into_messages(template, messages)
+
+        # Only the successful example should be injected
+        tool_calls = [m for m in result if m.get("role") == "assistant" and m.get("tool_calls")]
+        assert len(tool_calls) == 1
+        assert tool_calls[0]["tool_calls"][0]["function"]["name"] == "read_file"
+
+    def test_increments_usage(self, tmp_templates):
+        template = SessionTemplate(name="usage-test", task_type=TaskType.CODE, examples=[
+            ToolCallExample(tool_name="execute_code", args={}, success=True),
+        ])
+        tmp_templates.save_template(template)
+
+        tmp_templates.inject_into_messages(template, [{"role": "system", "content": "x"}])
+        assert template.usage_count == 1
+
+    def test_empty_template_returns_original(self, tmp_templates):
+        template = SessionTemplate(name="empty", task_type=TaskType.CODE, examples=[])
+        messages = [{"role": "user", "content": "hi"}]
+        result = tmp_templates.inject_into_messages(template, messages)
+        assert result == messages
+
+    def test_no_template_returns_original(self, tmp_templates):
+        messages = [{"role": "user", "content": "hi"}]
+        result = tmp_templates.inject_into_messages(None, messages)
+        assert result == messages

tools/session_templates.py

@@ -0,0 +1,418 @@
+"""
+Session templates for code-first seeding.
+
+Research finding: Code-heavy sessions (execute_code dominant in first 30 turns)
+improve over time. File-heavy sessions degrade. The key is deterministic
+feedback loops, not arbitrary context.
+
+This module provides:
+1. Task type classification (CODE, FILE, RESEARCH, MIXED)
+2. Template extraction from completed sessions
+3. Template storage (~/.hermes/session-templates/)
+4. Template injection into new sessions
+5. CLI interface for template management
+
+Closes #329.
+"""
+
+from __future__ import annotations
+
+import json
+import os
+import sqlite3
+from dataclasses import asdict, dataclass, field
+from enum import Enum
+from pathlib import Path
+from typing import Any, Optional
+
+
+# ---------------------------------------------------------------------------
+# Constants
+# ---------------------------------------------------------------------------
+
+HERMES_HOME = Path(os.environ.get("HERMES_HOME", str(Path.home() / ".hermes")))
+TEMPLATES_DIR = HERMES_HOME / "session-templates"
+SESSIONS_DB = HERMES_HOME / "state.db"
+
+# Tool classification sets
+CODE_TOOLS = frozenset({"execute_code", "code_execution"})
+FILE_TOOLS = frozenset({"read_file", "write_file", "patch", "search_files"})
+RESEARCH_TOOLS = frozenset({"web_search", "web_fetch", "browser_navigate", "browser_snapshot"})
+
+# Dominance threshold for task type classification
+DOMINANCE_THRESHOLD = 0.6
+
+# Default max examples to extract per template
+DEFAULT_MAX_EXAMPLES = 10
+
+
+# ---------------------------------------------------------------------------
+# Data model
+# ---------------------------------------------------------------------------
+
+class TaskType(str, Enum):
+    CODE = "code"
+    FILE = "file"
+    RESEARCH = "research"
+    MIXED = "mixed"
+
+
+@dataclass
+class ToolCallExample:
+    """A single tool call with its result, used as a template example."""
+    tool_name: str
+    args: dict[str, Any]
+    result_preview: str = ""
+    success: bool = True
+
+
+@dataclass
+class SessionTemplate:
+    """A session template containing tool call examples for seeding."""
+    name: str
+    task_type: TaskType
+    examples: list[ToolCallExample] = field(default_factory=list)
+    source_session_id: str = ""
+    created_at: str = ""
+    usage_count: int = 0
+    description: str = ""
+
+
+# ---------------------------------------------------------------------------
+# Core logic
+# ---------------------------------------------------------------------------
+
+class SessionTemplates:
+    """Manages session templates for code-first seeding."""
+
+    def __init__(self, templates_dir: Optional[Path] = None):
+        self.templates_dir = templates_dir or TEMPLATES_DIR
+        self.templates_dir.mkdir(parents=True, exist_ok=True)
+
+    def classify_task_type(self, tool_calls: list[dict[str, Any]]) -> TaskType:
+        """Classify a session's task type based on tool call patterns.
+
+        Uses 60% threshold for dominant type.
+        """
+        if not tool_calls:
+            return TaskType.MIXED
+
+        total = len(tool_calls)
+        code_count = 0
+        file_count = 0
+        research_count = 0
+
+        for tc in tool_calls:
+            name = tc.get("name", tc.get("tool_name", "")).lower()
+            if name in CODE_TOOLS:
+                code_count += 1
+            elif name in FILE_TOOLS:
+                file_count += 1
+            elif name in RESEARCH_TOOLS:
+                research_count += 1
+
+        code_ratio = code_count / total
+        file_ratio = file_count / total
+        research_ratio = research_count / total
+
+        if code_ratio >= DOMINANCE_THRESHOLD:
+            return TaskType.CODE
+        if file_ratio >= DOMINANCE_THRESHOLD:
+            return TaskType.FILE
+        if research_ratio >= DOMINANCE_THRESHOLD:
+            return TaskType.RESEARCH
+        return TaskType.MIXED
+
+    def extract_from_session(
+        self,
+        session_id: str,
+        max_examples: int = DEFAULT_MAX_EXAMPLES,
+    ) -> list[ToolCallExample]:
+        """Extract tool call examples from a completed session.
+
+        Reads from the SQLite session database.
+        """
+        examples: list[ToolCallExample] = []
+
+        db_path = SESSIONS_DB
+        if not db_path.exists():
+            return examples
+
+        try:
+            conn = sqlite3.connect(str(db_path))
+            conn.row_factory = sqlite3.Row
+
+            rows = conn.execute(
+                "SELECT messages FROM sessions WHERE session_id = ? ORDER BY created_at DESC LIMIT 1",
+                (session_id,),
+            ).fetchone()
+
+            if not rows:
+                conn.close()
+                return examples
+
+            messages = json.loads(rows["messages"])
+
+            # Extract tool calls from assistant messages
+            for msg in messages:
+                if msg.get("role") != "assistant":
+                    continue
+                tool_calls = msg.get("tool_calls", [])
+                if not tool_calls:
+                    continue
+
+                for tc in tool_calls:
+                    if len(examples) >= max_examples:
+                        break
+
+                    fn = tc.get("function", {})
+                    name = fn.get("name", "")
+                    if not name:
+                        continue
+
+                    try:
+                        args = json.loads(fn.get("arguments", "{}"))
+                    except (json.JSONDecodeError, TypeError):
+                        args = {}
+
+                    # Find the corresponding tool result
+                    result_preview = ""
+                    success = True
+                    tc_id = tc.get("id", "")
+
+                    for result_msg in messages:
+                        if (result_msg.get("role") == "tool"
+                                and result_msg.get("tool_call_id") == tc_id):
+                            content = result_msg.get("content", "")
+                            result_preview = str(content)[:200]
+                            # Heuristic: errors contain common failure markers
+                            if any(marker in result_preview.lower() for marker in ("error", "failed", "traceback", "exception")):
+                                success = False
+                            break
+
+                    examples.append(ToolCallExample(
+                        tool_name=name,
+                        args=args,
+                        result_preview=result_preview,
+                        success=success,
+                    ))
+
+            conn.close()
+        except Exception:
+            pass
+
+        return examples
+
+    def create_template(
+        self,
+        session_id: str,
+        name: Optional[str] = None,
+        description: str = "",
+        max_examples: int = DEFAULT_MAX_EXAMPLES,
+    ) -> Optional[SessionTemplate]:
+        """Create a template from a session's tool call history."""
+        examples = self.extract_from_session(session_id, max_examples)
+        if not examples:
+            return None
+
+        tool_calls_for_type = [{"name": e.tool_name} for e in examples]
+        task_type = self.classify_task_type(tool_calls_for_type)
+
+        template_name = name or f"{task_type.value}_{session_id[:8]}"
+
+        from datetime import datetime
+        template = SessionTemplate(
+            name=template_name,
+            task_type=task_type,
+            examples=examples,
+            source_session_id=session_id,
+            created_at=datetime.utcnow().isoformat() + "Z",
+            description=description or f"Auto-extracted from {session_id}",
+        )
+
+        self.save_template(template)
+        return template
+
+    def save_template(self, template: SessionTemplate) -> Path:
+        """Save a template to disk."""
+        path = self.templates_dir / f"{template.name}.json"
+        data = {
+            "name": template.name,
+            "task_type": template.task_type.value,
+            "examples": [asdict(e) for e in template.examples],
+            "source_session_id": template.source_session_id,
+            "created_at": template.created_at,
+            "usage_count": template.usage_count,
+            "description": template.description,
+        }
+        path.write_text(json.dumps(data, indent=2, sort_keys=True) + "\n")
+        return path
+
+    def get_template(self, task_type: TaskType) -> Optional[SessionTemplate]:
+        """Get the best template for a given task type."""
+        templates = self.list_templates(task_type)
+        if not templates:
+            return None
+
+        # Prefer templates with more usage (proven useful)
+        templates.sort(key=lambda t: t.usage_count, reverse=True)
+        return templates[0]
+
+    def list_templates(self, task_type: Optional[TaskType] = None) -> list[SessionTemplate]:
+        """List all templates, optionally filtered by type."""
+        templates: list[SessionTemplate] = []
+
+        for path in sorted(self.templates_dir.glob("*.json")):
+            try:
+                data = json.loads(path.read_text())
+                examples = [ToolCallExample(**e) for e in data.get("examples", [])]
+                template = SessionTemplate(
+                    name=data["name"],
+                    task_type=TaskType(data["task_type"]),
+                    examples=examples,
+                    source_session_id=data.get("source_session_id", ""),
+                    created_at=data.get("created_at", ""),
+                    usage_count=data.get("usage_count", 0),
+                    description=data.get("description", ""),
+                )
+                if task_type is None or template.task_type == task_type:
+                    templates.append(template)
+            except Exception:
+                continue
+
+        return templates
+
+    def delete_template(self, name: str) -> bool:
+        """Delete a template by name."""
+        path = self.templates_dir / f"{name}.json"
+        if path.exists():
+            path.unlink()
+            return True
+        return False
+
+    def inject_into_messages(
+        self,
+        template: SessionTemplate,
+        messages: list[dict[str, Any]],
+    ) -> list[dict[str, Any]]:
+        """Inject template examples into a session's messages.
+
+        Inserts tool call examples after system messages to establish
+        feedback loops early.
+        """
+        if not template or not template.examples:
+            return messages
+
+        # Build injection messages
+        injection: list[dict[str, Any]] = []
+
+        # System note about the template
+        injection.append({
+            "role": "system",
+            "content": (
+                f"[Session Template: '{template.name}' ({template.task_type.value})]\n"
+                f"The following are examples of successful tool calls from a similar session. "
+                f"Use them as patterns for your own tool usage."
+            ),
+        })
+
+        # Add example tool call/result pairs
+        for ex in template.examples:
+            if not ex.success:
+                continue  # Only inject successful examples
+
+            injection.append({
+                "role": "assistant",
+                "content": None,
+                "tool_calls": [{
+                    "id": f"template_{template.name}_{ex.tool_name}",
+                    "type": "function",
+                    "function": {
+                        "name": ex.tool_name,
+                        "arguments": json.dumps(ex.args),
+                    },
+                }],
+            })
+            injection.append({
+                "role": "tool",
+                "tool_call_id": f"template_{template.name}_{ex.tool_name}",
+                "content": ex.result_preview or "(example result)",
+            })
+
+        # Find insertion point: after system messages
+        insert_idx = 0
+        for i, msg in enumerate(messages):
+            if msg.get("role") == "system":
+                insert_idx = i + 1
+            else:
+                break
+
+        # Insert
+        result = messages[:insert_idx] + injection + messages[insert_idx:]
+
+        # Update usage count
+        template.usage_count += 1
+        self.save_template(template)
+
+        return result
+
+
+# ---------------------------------------------------------------------------
+# CLI
+# ---------------------------------------------------------------------------
+
+def _cli():
+    """Simple CLI for session template management."""
+    import argparse
+    import sys
+
+    parser = argparse.ArgumentParser(description="Session template management")
+    sub = parser.add_subparsers(dest="command")
+
+    # list
+    list_cmd = sub.add_parser("list", help="List templates")
+    list_cmd.add_argument("--type", choices=["code", "file", "research", "mixed"])
+
+    # create
+    create_cmd = sub.add_parser("create", help="Create template from session")
+    create_cmd.add_argument("session_id", help="Session ID to extract from")
+    create_cmd.add_argument("--name", help="Template name")
+    create_cmd.add_argument("--max-examples", type=int, default=10)
+
+    # delete
+    delete_cmd = sub.add_parser("delete", help="Delete template")
+    delete_cmd.add_argument("name", help="Template name")
+
+    args = parser.parse_args()
+    tm = SessionTemplates()
+
+    if args.command == "list":
+        task_type = TaskType(args.type) if args.type else None
+        templates = tm.list_templates(task_type)
+        if not templates:
+            print("No templates found.")
+            return
+        for t in templates:
+            print(f"  {t.name:30s} {t.task_type.value:10s} {len(t.examples)} examples, used {t.usage_count}x")
+
+    elif args.command == "create":
+        template = tm.create_template(args.session_id, name=args.name, max_examples=args.max_examples)
+        if template:
+            print(f"Created template: {template.name} ({template.task_type.value}, {len(template.examples)} examples)")
+        else:
+            print(f"No tool calls found in session {args.session_id}")
+            sys.exit(1)
+
+    elif args.command == "delete":
+        if tm.delete_template(args.name):
+            print(f"Deleted template: {args.name}")
+        else:
+            print(f"Template not found: {args.name}")
+            sys.exit(1)
+
+    else:
+        parser.print_help()
+
+
+if __name__ == "__main__":
+    _cli()