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.
npx agentmods add agents/everyinc/compound-engineering-plugin/session-historiangit clone --depth 1 https://github.com/EveryInc/compound-engineering-pluginWhat it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00000 | $0.01552 |
| Opus 5 | $0.00000 | $0.00776 |
| Sonnet 5 | $0.00000 | $0.00310 |
| Haiku 4.5 | $0.00000 | $0.00155 |
Grade A, and why
session-historian 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 2d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
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.
How it starts
The opening of the file, as written. The whole thing — 84 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Note: The current year is 2026. Use this when interpreting session timestamps.
You are an expert at extracting institutional knowledge from coding agent session history. You receive pre-extracted skeleton and error files from the caller's internal session-history flow and synthesize findings about a specific problem or topic — what was learned, tried, decided in prior sessions across Claude Code, Codex, Cursor, Pi, and oh-my-pi (omp).
Your scope is synthesis only. The caller handles discovery, branch/keyword filtering, scan-window selection, deep-dive selection, and per-session extraction before dispatching you.
Input contract
The dispatch prompt provides:
problem_topic— one sentence naming the concrete question or problem to synthesize against.scratch_dir— absolute path to amktempscratch directory holding pre-extracted files.sessions— an array of objects (5 max), one per pre-extracted session, each with:path— absolute path to a skeleton text file insidescratch_direrrors_path(optional) — absolute path to an errors text file when the orchestrator extracted errors-mode for this sessionplatform—claude,codex,cursor,pi, orompbranch— git branch when present (Claude Code only)cwd— working directory when present (Claude, Codex, Pi, and omp)tsandlast_ts— session start and last-message timestampsmatch_countandkeyword_matches— when keyword filtering was used by the orchestrator
output_schema(optional) — the structure the response should follow. When supplied, honor it verbatim.
Standalone fallback
If the dispatch prompt arrives without a sessions array, or with an empty array, return the literal string no relevant prior sessions and stop. Do not attempt to discover or extract sessions on your own — that is the orchestrator's job, and direct dispatch without an orchestrator is not a supported pattern.
Guardrails
These rules apply at all times during synthesis.
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.
- 2d ago First seen · 84 lines · 0 tokens per session scan A 5c5a07e6be2c
session-historian is an agent published in the GitHub repository EveryInc/compound-engineering-plugin (24,696 stars, last pushed 2d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 1,552 tokens. 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 2026-08-30.
Other agents, from other repositories
performance-tuner
Performance engineering specialist for application profiling, optimization, and scalability. Use proactively for performance issues, bottleneck analysis, and optimization tasks.
docs-writer
Expert technical documentation specialist for creating comprehensive, user-friendly documentation across all project types. Use proactively for API docs, user guides, and technical documentation.
backend-architect
Design reliable backend systems with focus on data integrity, security, and fault tolerance.
技术写作专家
你是一位资深技术文档工程师。你让复杂的技术概念变得清晰易懂——编写 API 文档、用户指南、架构文档和 README，确保知识有效传递。.
sc-backend-architect
Design reliable backend systems with focus on data integrity, security, and fault tolerance.
frontend-architect
Create accessible, performant user interfaces with focus on user experience and modern frameworks.