tack

Tack gives your agents persistent project memory that stays accurate instead of going stale.

Static instruction files drift the moment the code changes. Tack keeps a shared record in ./.tack/ and checks that memory against the actual codebase, so the next agent starts from context that is still trustworthy.

Install And Prove It Works

Install Tack. If you prefer not to install globally, use npx tack-cli@latest instead of tack.

npm install -g tack-cli

Initialize the repo and install your agent startup instructions once.

tack init
tack setup-agent

Keep tack watch open in a second terminal as live proof.

tack watch

Start the MCP server from the repo root with a visible agent label.

TACK_AGENT_NAME=claude tack mcp

On Windows PowerShell, set the label like this instead:

$env:TACK_AGENT_NAME="claude"
tack.cmd mcp

Confirm the canonical trust loop in tack watch:

READY means the MCP session connected
READ means the agent read tack://session or another Tack context resource
WRITE means the agent wrote memory back with checkpoint_work, log_decision, or log_agent_note

If you see READY, READ, and WRITE, the agent is actually using Tack.

At the end of a session, package a handoff:

tack handoff

Read the full guides:

What Tack Actually Does

Keep implementation facts aligned with the real codebase
Stop stale project instructions from misleading the next agent
Preserve decisions, blockers, discoveries, and partial work across sessions
Show live proof that agents are reading current context and writing memory back
Carry context across session boundaries with handoffs and MCP startup resources

Why This Matters

The real failure mode is stale context, not just missing context
Every repeated question like "what framework are we using?" is a context failure
Drift detection keeps Tack from lying to the next agent when the code has changed
Decisions explain why the system looks the way it does before the agent asks
Handoffs let context survive session boundaries without another interview

Common Workflow

Initialize Tack once at the repo root:

tack init

Install agent instructions once per repo:

tack setup-agent

Use this canonical proof loop when wiring up an agent:

tack watch
TACK_AGENT_NAME=claude tack mcp

On Windows PowerShell:

tack watch
$env:TACK_AGENT_NAME="claude"
tack.cmd mcp

tack watch is the live proof. The happy path is simple: READY, then READ, then WRITE.

Example:

[READY][claude] connected to Tack MCP
[READ][claude] read session context
[WRITE][claude] checkpointed work

v1 does not ship a standalone tack check-in command. Write-back stays behind MCP tools like checkpoint_work plus tack handoff.

During normal work:

tack status
tack watch

If you use more than one agent, give each MCP server its own TACK_AGENT_NAME so tack watch can show who read context, who checked rules, and who wrote memory back.

Example Workflows

New Agent Session

Open a new agent window in a repo that already uses Tack:

tack watch
TACK_AGENT_NAME=claude tack mcp

On Windows PowerShell:

tack watch
$env:TACK_AGENT_NAME="claude"
tack.cmd mcp

The agent reads tack://session, sees the current focus and recent work, and starts from maintained context instead of re-learning the repo. tack watch shows the read live so you know the agent is grounded in current project memory.

Structural Change

The agent wants to add a dependency or introduce a new boundary.

Instead of guessing from stale instructions, it calls check_rule first. That gives a compact yes/no-with-context guardrail check before the architecture changes.

End Of Session

The agent made changes, found one blocker, and left partial work.

Instead of making the next session reconstruct what happened, it calls checkpoint_work once. Tack saves a summary, discoveries, decisions, and related files so the next session inherits usable context immediately.

Learn More

Notes

offline only, no hidden network calls in Tack's project-memory engine
writes are guarded to ./.tack/
Python virtual environments are ignored during scans (venv, .venv, site-packages) to reduce false positives

tack-cli

Quick Install