What is SessionStart?

A session-start hook that adds the project's engineering rules to the coding agent's context when a session begins.

Use it to enforce written planning and worklog habits automatically at the start of each coding session.

It reminds the agent to estimate work, record every change, keep the current initiative plan updated, and refresh planning documents before the session ends.

SessionStart — Hook by markskrypka

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods

npx agentmods add hooks/markskrypka/stem/session-start

Clone the repo

git clone --depth 1 https://github.com/markskrypka/stem

Per session not measured What this adds to a session before it is invoked.

When invoked not measured Not applicable: nothing here is loaded into a session.

Security scan A 0 findings. Scan, not verified.

Origin original No closer match found in the catalogue.

Security

Grade A, and why

SessionStart scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the commands this hook runs, not an audit. A hook is shell that executes on your machine at the event it names, which is why every command in it is printed with what was found.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

hooks/hooks.json · 13 lines

What it actually says

{
  "SessionStart": [
    {
      "hooks": [
        {
          "type": "command",
          "command": "node -e \"console.log(JSON.stringify({hookSpecificOutput:{additionalContext:'This project runs a written engineering discipline: size the work before doing it, append a docs/planning/worklog.md entry for every change, keep the active initiative work.md current, and refresh planning docs before ending or compacting.'}}))\"",
          "timeout": 10000
        }
      ]
    }
  ]
}

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

yesterday First seen · 13 lines scan A 3ba8a01c8915

Subscribe to this mod's changes

SessionStart is a hook published in the GitHub repository markskrypka/stem (2 stars, last pushed 27d ago), licensed Apache-2.0. Its token cost is not measured: a hook is shell that never enters the context. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

Planning Productivity agent-skills ai-agents claude-code claude-code-plugin claude-code-plugins-marketplace cursor

PreToolUse

Runs before the agent uses a tool for mcp__.*__(get_data_from_fields, get_sql_from_fields, initiate_analysis), mcp__.*__(create_object, update_object, create_entity, import_tables, create_context_item, update_context_item), mcp__.*__(list_entities, get_entity, get_field, search_model, list_databases, list_schemas…

honeydew-ai/honeydew-ai-coding-agents-plugins · not measured

SessionStart

Getting it into your agent

Grade A, and why

Nothing flagged

What it actually says

What this file has done since we first saw it

Other hooks, from other repositories

PreToolUse

Stop

SubagentStop

SubagentStop

SubagentStart

SessionStart