io.github.stringsofthemind-oss/once
NPM · @ONCE-AGENT/MCP · SCANNED SEP 25
Execution-safety MCP for AI coding agents protecting consequential writes from unsafe retries.
Available components
How this component scores in each security and reliability category. Every signal is checked automatically from public evidence about the published package, including repeated runs of it in an isolated sandbox, and we only credit what we can confirm. How we score → Why this is hard to score →
Supply Chain Security100
- No malware found by supply-chain analysis.Pass
- No known CVEs affecting this package version or its production dependencies.Pass
- No install/post-install scripts declared.Pass
- 0 of 5 dependencies flagged as unhealthy. View diagnostics → Pass
Provenance & Transparency45
- Source repository is publicly reachable at the declared URL. View diagnostics → Pass
- Provenance check failed: no build-provenance attestation is published. See how to fix → View diagnostics → Fail
- Clear OSI-approved license (MIT).Pass
- Actively maintained (last published 2 days ago).Pass
- Disclosure check failed: no security disclosure policy was found in the source repository. See how to fix → Fail
Schema Quality & AI Usability80
- AI-judged instruction clarity (excellent).Pass
- Tool/resource definitions use about 582 tokens (~72/item across 8 items; 8 tools + 0 resources), lean.Pass
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management17
- Stability observed for 5 of 30 days with no destabilising changes; credit accrues until the full window elapses.Partial
Tool Coverage90
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 69% of tool parameters carry a description.Partial
Tool Safety100
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- We read all 8 captured tool definition(s), and no name or description among them implies an irreversible operation.Pass
- An AI judge read all 8 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities100
- Implements a current MCP spec version (2026-07-28).Pass
How do I install the io.github.stringsofthemind-oss/once MCP server?
io.github.stringsofthemind-oss/once runs locally as an npm package, launched with npx -y @once-agent/mcp. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.
npm · @once-agent/mcp
claude mcp add stringsofthemind-oss-once -- npx -y @once-agent/mcp
{
"mcpServers": {
"stringsofthemind-oss-once": {
"command": "npx",
"args": [
"-y",
"@once-agent/mcp"
]
}
}
} {
"servers": {
"stringsofthemind-oss-once": {
"command": "npx",
"args": [
"-y",
"@once-agent/mcp"
]
}
}
} codex mcp add stringsofthemind-oss-once -- npx -y @once-agent/mcp
{
"$schema": "https://opencode.ai/config.json",
"mcp": {
"stringsofthemind-oss-once": {
"type": "local",
"command": [
"npx",
"-y",
"@once-agent/mcp"
],
"enabled": true
}
}
} openclaw mcp add stringsofthemind-oss-once --command npx --arg -y --arg @once-agent/mcp
mcp_servers:
stringsofthemind-oss-once:
command: "npx"
args: ["-y", "@once-agent/mcp"] {
"McpServers": {
"stringsofthemind-oss-once": {
"Transport": "stdio",
"Command": "npx",
"Arguments": [
"-y",
"@once-agent/mcp"
]
}
}
} assistant mcp add stringsofthemind-oss-once -t stdio -c npx -a -y @once-agent/mcp
{
"mcpServers": {
"stringsofthemind-oss-once": {
"command": "npx",
"args": [
"-y",
"@once-agent/mcp"
]
}
}
} Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.
- 25 Sept 26 +1
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
- 22 Sept 26 +1
- Tool safety: pass → unverified ▼ security
- Stability: Stability not yet verified: we do not have a sandbox capture of the MCP schema this version of the package serves yet. security
- Capabilities: pass → unverified ▼ functional
- Tool coverage: 100 → unverified ▼ functional
- Stability: unverified → 0.07 ▲ functional
- First check of Schema quality: unverified functional
- Package version: 0.1.2 → 0.1.3 functional
- 21 Sept 26 +11
- Known CVEs: unverified → pass ▲ security
- Dependency health: unverified → 1.00 ▲ functional
- 20 Sept 26 60
First indexed and scored.
Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.
Captured 25 Sept 2026 · Analysed npm/@once-agent/mcp@0.1.3
Provenance No attestation
The registry publishes no build provenance for this version, so there is nothing to verify.
| Result | No attestation |
|---|---|
| Ecosystem | npm |
Background: How many MCP packages publish verified provenance →
Dependencies 5 packages
| Packages resolved | 5 |
|---|---|
| Tree resolution | Complete |
Background: SBOMs and build attestations, explained →
The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →
once_apply_protection Apply Once protection ~75
Transactionally apply exactly one PATCHABLE Once protection candidate. This modifies source code and creates a backup. Call once_plan_protection first, show the proposed target to the user, and only proceed after explicit approval.
| Name | Type | Req | Description |
|---|---|---|---|
| confirm | string | yes | Explicit confirmation token. Must be exactly APPLY. |
| projectPath | string | – | – |
No output schema declared.
No examples provided.
once_assess_project Assess project for unsafe retry paths ~94
Use this first when code performs payments, refunds, payouts, bookings, orders, provisioning, database/API writes, consequential messaging, deployments, MCP writes, or other side effects. Scans the project for likely consequential operations without modifying files.
| Name | Type | Req | Description |
|---|---|---|---|
| includeEstimates | boolean | – | Include Once scanner estimates in the report. |
| projectPath | string | – | Absolute or relative project directory. Defaults to the MCP server working directory. |
No output schema declared.
No examples provided.
once_explain_risk Explain retry risk for a consequential operation ~101
Explain why a specific operation may need Once. Use when an agent or developer is deciding whether a payment, refund, booking, order, provisioning action, database/API mutation, webhook, deployment, MCP write, or other external side effect needs execution-safety protection.
| Name | Type | Req | Description |
|---|---|---|---|
| operation | string | yes | Plain-language description of the consequential operation. |
| retryScenario | string | – | Optional timeout, retry, crash, queue-redelivery, or ambiguous-failure scenario. |
No output schema declared.
No examples provided.
once_live_proof Get Once live-proof evidence and claim boundaries ~43
Return the current demonstrated Once proof, public evidence links, and safe claim boundaries. Use when deciding whether Once has evidence for duplicate suppression rather than relying on marketing language.
Input schema present but exposes no named parameters.
No output schema declared.
No examples provided.
once_plan_protection Plan Once protection ~66
Review candidate operations for Once protection without applying code changes. Use after once_assess_project to understand which call sites are patchable and why.
| Name | Type | Req | Description |
|---|---|---|---|
| includeAllConfidenceLevels | boolean | – | Include all confidence levels rather than the default candidate set. |
| projectPath | string | – | – |
No output schema declared.
No examples provided.
once_plan_setup Preview Once setup ~64
Preview how Once would be configured in a project without applying setup. Use after assessing a project and before allowing an agent to install or configure Once.
| Name | Type | Req | Description |
|---|---|---|---|
| projectPath | string | – | – |
| runtimeHttpTargetUrl | string | – | Optional HTTPS target for Runtime HTTP replay protection. |
No output schema declared.
No examples provided.
once_setup_project Install and configure Once ~89
Apply Once setup to a project. This may install dependencies and modify project files. Call once_plan_setup first, present the plan to the user, and only call this tool after explicit approval.
| Name | Type | Req | Description |
|---|---|---|---|
| confirm | string | yes | Explicit confirmation token. Must be exactly SETUP. |
| projectPath | string | – | – |
| runtimeHttpTargetUrl | string | – | Optional HTTPS target for Runtime HTTP replay protection. |
No output schema declared.
No examples provided.
once_verify_connection Verify Once Cloud connection ~50
Run Once Doctor to verify that ONCE_API_KEY is present, Once Cloud is reachable, the key is accepted, the truth endpoint works, and the safety probe passes. Does not print the API key.
Input schema present but exposes no named parameters.
No output schema declared.
No examples provided.
What is the io.github.stringsofthemind-oss/once MCP server?
io.github.stringsofthemind-oss/once is an MCP server listed in the public MCP registry as io.github.stringsofthemind-oss/once. Execution-safety MCP for AI coding agents protecting consequential writes from unsafe retries. This page covers its npm package (@once-agent/mcp).
Is the io.github.stringsofthemind-oss/once MCP server safe to use?
io.github.stringsofthemind-oss/once scores 73 out of 100 on VerifyMCP. We found no known CVEs affecting it as of 25 September 2026. It declares no install or post-install scripts. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.
What tools does the io.github.stringsofthemind-oss/once MCP server expose?
io.github.stringsofthemind-oss/once exposes 8 tools: once_assess_project, once_explain_risk, once_plan_setup, once_setup_project, once_plan_protection, and 3 more. Their descriptions and schemas cost roughly 582 tokens of context every time the server is loaded.
Is the io.github.stringsofthemind-oss/once MCP server still maintained?
io.github.stringsofthemind-oss/once is still listed as active in the MCP registry. We last reached this channel on 25 September 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.
What licence is the io.github.stringsofthemind-oss/once MCP server under?
io.github.stringsofthemind-oss/once declares the MIT licence, which is OSI-approved. That covers the source only, and says nothing about the cost of any service it calls.