Both can block a tool call before it runs, but they are built around different jobs. Obot is a broad, open-source platform that hosts your MCP servers, runs a registry and catalogue, and proxies clients through an authenticated gateway, with webhook filters you write to inspect and block calls. PolicyLayer is a focused, hosted control plane: deterministic, declarative policy on every call, with no enforcement code to write. Here is where each one fits.
Obot gives you an open-source platform plus a custom-code hook for interception. PolicyLayer gives you out-of-the-box declarative policy depth as a managed control plane. They genuinely compete, and can sit side by side.
PolicyLayer is the hosted gateway your MCP traffic runs through. It does not host or publish your servers. Its job is enforcement: every tool call is evaluated against deterministic, declarative, deny-by-default policy before it executes, with argument conditions, approval gates, per-person scoped credentials, and rate or spend limits as first-class primitives, no code to write. Recommended policy ships pre-classified across 220,000+ catalogued tools.
Obot is a broad, open-source (MIT) MCP platform from Obot AI. It hosts your MCP servers (Node, Python, containers via Docker or Kubernetes), runs a registry and catalogue, proxies clients such as Claude, Cursor, and VS Code through a single authenticated gateway, and ships its own chat client with multi-model support, RAG, and memory. It anchors access to your IdP, brokers upstream credentials centrally, and exposes webhook filters that can inspect a tool call and accept or reject it.
A broad self-hosted platform, versus a focused hosted policy layer.
| PolicyLayer | Obot | |
|---|---|---|
| Primary job | Enforce deterministic policy on every MCP tool call | Host, catalogue, and proxy MCP servers org-wide, with access control |
| Enforcement model | Deterministic, declarative, deny by default | Identity-anchored access plus webhook filters that accept or reject a call |
| Argument-level policy | First-class, no code (allow refund_payment only when amount is under $100) | Possible via filters you write (a custom MCP filter server or HTTP webhook); the only built-in filter shipped is PII redaction |
| Approvals | Built-in human approval gates | Not documented natively; webhook filters are accept or reject |
| Limits | Per-tool rate and spend limits as primitives | Not documented natively; build on top of the filter hook |
| Hosting | Routes the servers you already run; does not host them | Hosts and publishes servers, and serves a curated catalogue |
| Identity | Per-person scoped tokens issued against each upstream | IdP-anchored, with centralised token brokering so clients never hold upstream tokens |
| Audit | Every call logged with the tool, its arguments, and the decision | Audit logs and usage monitoring across servers and agents |
| Deployment | Hosted control plane; nothing to run | Open-source (MIT), self-hosted via Docker or Kubernetes; paid Enterprise Edition |
| Best fit | Out-of-the-box deterministic policy depth, owned by people who write rules | Teams tackling MCP sprawl who want to self-host hosting, catalogue, and proxy |
Deterministic, declarative rules, argument conditions, approval gates, and spend limits as primitives, instead of a custom webhook service per rule path you build and run.
The people who write policy are not the people who ship and operate enforcement services.
You want consistent control over tool calls without adopting a platform that also hosts, catalogues, and serves a chat client.
You would rather not operate a gateway and per-server shim yourself.
You want code ownership, own-cloud or air-gapped deployment, and no lock-in.
Not just police traffic: host MCP servers and offer a discoverable catalogue across the org.
Multi-model chat with RAG and memory, plus centralised token brokering, match how you want to work.
These are adjacent more often than mutually exclusive. Obot can host and publish your servers and run the catalogue, while PolicyLayer enforces deterministic per-call policy on the traffic. They compete head-on only for the buyer who wants a single gateway that controls what every agent can do: Obot wins on open-source, self-hosting, and breadth; PolicyLayer wins on out-of-the-box deterministic policy depth and a managed control plane.
Whatever your agents touch, the same engine, audit, and access model is doing the work underneath every rule you write.
Rules run as code, not model judgement: argument-level conditions, quotas, deny-by-default. The same call gets the same decision every time.
Writing policies →Your security or compliance team writes and attaches policy without ever holding the upstream credentials or grant tokens.
Roles →Every call is logged with its decision and the rule that fired, attributed to the identity, in an append-only record. Argument values are redacted, never stored.
Logs & security →Upstream secrets are encrypted at rest and injected by the gateway. The agent only ever holds a scoped token.
Logs & security →Every person and agent connects with its own scoped grant. Rotate or revoke any one of them instantly, without disrupting the rest.
Core concepts →Hosted gateway. Point your clients at it, register a server, issue a token. Nothing to install.
Quick start →Yes, but as filters you write. Obot's filter framework (a custom MCP filter server or HTTP webhook) can inspect a call's arguments and accept, reject, or mutate it, scoped to specific tools. Its built-in filters cover PII redaction; argument-level allow or deny rules are a custom filter you build and host. PolicyLayer evaluates argument conditions as declarative configuration, with no code to run.
They are not documented as native primitives; you would build them on top of the filter hook. PolicyLayer ships approval gates and per-tool rate and spend limits out of the box.
No. PolicyLayer is a hosted control plane. Obot is MIT-licensed and fully self-hostable, which is the right call if code ownership or air-gapped deployment is a requirement.
No. PolicyLayer routes the servers you already run and enforces policy on the calls. Obot can host and publish servers and serve a catalogue.
Deterministic, deny-by-default policy on every MCP tool call: argument conditions, approval gates, per-identity scopes, and spend limits as primitives, with a tamper-proof audit log. Route your existing MCP servers through the gateway, live in minutes.
Instant setup, no code required.