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 commands/backchainai/backchain-plugins/checkpointgit clone --depth 1 https://github.com/backchainai/backchain-pluginsWhat 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 | $0.00520 |
| Opus 5 | $0.00000 | $0.00260 |
| Sonnet 5 | $0.00000 | $0.00104 |
| Haiku 4.5 | $0.00000 | $0.00052 |
Grade A, and why
checkpoint 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 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 — 70 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Command: checkpoint
Create or update .memory/ with current conversation state.
Trigger
/engram:working checkpoint or natural language: "checkpoint our progress", "save working memory".
Behavior
- Determine the current working directory.
- Check whether
.memory/exists; create it if not. - For each template file (
todos.md,decisions.md,questions.md):- If the file exists: read current contents, append new items, update the timestamp.
- If it does not exist: create from the template in
${CLAUDE_SKILL_DIR}/templates/.
- Analyze the current conversation to extract:
- Todos: action items, next steps, agreed-upon tasks.
- Decisions: explicit choices with rationale, trade-off resolutions.
- Questions: open issues, deferred decisions, knowledge gaps.
- Update each file's
Last Updatedtimestamp usingdate -Iseconds. - Confirm with a summary.
Extraction guidelines
Todos
Look for:
- Explicit action items ("we need to…", "next step is…").
- Agreed-upon tasks ("let's do X").
- Follow-up items ("we should also…").
Categorize as: In Progress, Blocked, Completed, Backlog.
Decisions
Look for:
- Explicit choices ("we decided to use X").
- Trade-off resolutions ("X over Y because…").
- Architecture / design selections.
- Tool / library selections.
Capture: context, decision, rationale, alternatives considered.
Questions
Look for:
- Unresolved discussions ("we still need to figure out…").
- Deferred decisions ("let's decide later…").
- Knowledge gaps ("I'm not sure about…").
- External dependencies ("we need to ask…").
Capture: question, context, what it blocks, candidate answers.
Output format
Checkpointed working memory (.memory/):
- {N} todos ({new} new, {existing} existing)
- {N} decisions ({new} new, {existing} existing)
- {N} questions ({new} new, {existing} existing)
Constraints
- Append; never overwrite. Preserving prior session context is the whole point.
- Preserve template structure (headings, formatting).
- Use RFC 3339 timestamps from
date -Iseconds. - Keep items concise but include enough context to resume cold.
- If no new items in a category, skip its file (do not create empty entries).
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 · 70 lines · 0 tokens per session scan A 447fe0ee72ed
checkpoint is a command published in the GitHub repository backchainai/backchain-plugins (4 stars, last pushed 27d ago), licensed Apache-2.0. It costs nothing until one of its globs matches a file; then it loads 520 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 2026-08-31.
Other commands, from other repositories
benchmark
Run a TAU-bench evaluation end-to-end and present results.
checkout-branch
Switch to an existing branch by checking out its worktree, or creating one if needed.
create-branch
Create a new git branch with an associated worktree following the project naming convention.
create-pr
Create a pull request for the current branch against main.
list-branches
List project branches with their worktree status.
remove-branch
Remove a branch and its associated worktree.