MCP ohne Governance ist eine nicht katalogisierte API, eine Ebene höher.
Ein kleiner Model Context Protocol-Server, der einen statischen OpenAPI-Katalog, einen schriftlichen Vertrag und eine explizite Deny-Liste veröffentlicht. Er ist eine Referenzfläche — keene Plattform und kein SaaS.
Bruno Char oder de Ouino, Lösungsarchitekt.
MCP host (Cursor, Claude, …)
|
| stdio
v
+---------------------------+
| mcp-server-reference |
| |
| tools = catalog lookup |
| resources = contract |
| deny-list = interface |
+---------------------------+
|
| imported modules only
v
orders | identity | billing
(OpenAPI snippets, no fetch)Teams verdrasten MCP-Server so, wie sie early Shadow-APIs verdrasten: ein Prozess, ein neue mächtte Tools, kein Inventar, kein Eigntümer, keine Aussagen darüber, was das Proz nicht tun darf.
Ein Tool, das eine URL akzeptiert, ist ein HTTP-Proxy. Ein Tool, das eine Shell-Zeichenkette akzeptiert, ist Remote Code-Ausführung. Ein Tool, das process.env ausgibt, ist die Exfiltration der Zugangasdaten. Das Protokoll macht diese Formen nicht sicher. Sie als „Tools“ zu nennen, verbirgt sie nur von den Menschen, die APIs prüfen.
Related MCP server: enterprise-mcp
Komponente | Rolle | |
TypeScript MCP-Server ( | stdio-Prozess, den ein Host starteen kann | |
Fünf Toolen | auflisten / nachschen / berschreiben. Keine Ausführung. | |
Für Ressoucen | Vertrag, Deny-Liste, Katalog-Index, Pro-API-Spezifikation | |
Kontent-ID | Menscher “lesbar" manigest der Oberfläche | |
Abgeschlosenie Liste der Fähigkeiten, die nicht hinzugefügt werden | ||
[DR-0001](docs/adr/0001-governed-mcp-suf seem) | Warum/de Deny-Liste Teil der Oberfläche ist |
The Katalog ist is a Drei Labor-Open API-Dokumente, die in den Prozess kompiliert werden. (orders, identity, billing). The .invalid-TLD .invalid in die Specs. Der Prozess ruft sie nie auf.
Kein Apidex. Apidex ist die produktfrageben – das response (ventar, Lebenszyexus, MCP-Governance). Dieses Repos ist an öffliche "in ehrlicher? Server is not" ein schriftleches Nein.
Kein MCP-Sicherhofs-Gateway. Kein OAuth, keene P-Principal-Allowlist, kein Audit-Export. Das ist ein spaterer Baustein.
Keine Kunden–Case–Studie. Keine erfundenene Zahl of Servern, Tokens, or „Shadow MCP um N% reduziert“ar.
Node 20+. TypeScript strikt. Kein Dateisystem-Zaust-Durchlauf. Kein fetch. Kein child_process.
Tool-Eingaben sind geschlossen: Slugs, HTTP-Methoden, exakte Pfad-Templates, Enu-Mehrungen der Deny-Liste.
billing ist absichtlich deprecated. Ein Katalog, der ausgelaufene APIs versteckt, lässt Integrationen verrotten.
Der veröffentlichte Anteil von Identity enthält keine Passwort- oder Token-Endpunkte. Die eingeschränkte Klassifizierung ist Metadaten, – nicht Theater.
Risiko | Wie es sich in MCP zeigt | Kontrolle hier |
SSRF |
| Keine URL–ugumente. Die Specs werden importiert; artifacts |
RCE |
| Nicht implementiert. Stattdessen: |
Exfiltration von Secrets |
| Keine env- oder Pfad-Tools. Keine Geheimnisse im Repository. |
Prompt-Injektion über Specuish | Remote-OpenAPI, die Anweisungen enthält | Kataloge is reviewed git content. |
Verwirrter Stellvertretter | Host–User gewährt den Server; das Modell wählt das Tooluut | Kleine Oberfläche. Vertrag ist auflistbar. |
Schatten–Argsführung | Lookup–Tool, das fundamental die Live-APIs aufruft |
|
Das ist "A Threat–notiz, no vollSTRIDEModel einer value of situation. If you connect this server to a [missing]. The server is still not. "You still trust Host and Modell. Dieses Vertrauen abzubahnen is Gateway–Areit.
npm install
npm test
npm run typecheck
npm run inspect # prints the contract JSON
npm run buildIstio-Server (der ein Host startet):
npm start
# or, without a prior build:
npm run devGeben Sie in diesen Prozess nichts. MCP ist JSON-RPC on stdin/stdout. Sprich es von einem Host.
{
"mcpServers": {
"catalog": {
"command": "node",
"args": ["/absolute/path/to/mcp-server-reference/dist/index.js"]
}
}
}Build first. The Host musz Node starteen können. Nach dem Verb if you call inspect_contract or lies mcp://contract.
npm run inspectDu shouldst die fünf Tools, the four Ressourcen and the seven Deny-List-Ids.
OpenAPI-Governance hat bereits ein Vokabular: Eigentümer, Lebenszyklus, Breaking Change, Deprecation, „diese Operation ist nicht öffentlich“. MCP ist dazu gekommen und hat dieses Vokabular vergessen.
Appi-Praxis | MCP-Aquivalent in diesem Repositorium |
Veröffentlichte OpenAPI |
|
Pfad-Allowlist | Kataloge-IDs + exakte Operationen |
„Exponiere /admin nicht“ | |
Deprecated API bleibt gelistet |
|
Vertragstest in der CI |
|
Wer symbologk a PR, der einen undokumentiert REST–Enndpont hinzügt, sollte auch den PR able hnen, der ein supp undokumentierten MCP-Tool hinzüfgt.
Die produktiere Version of die Problems – AP– und API-List, "-Inventar" – und MCP-Servern, Lebeszyklus, Review – ist Apidex. Dies Repos implementiert siege nicht. Es zeigt the Grundelement, das ein Katalog annehmen würde: ein Server, der sich selbst describe kann and angeben kann, was able.
Ein Demo that is a dis Belghen enthusiast. Beeendrük. It also beibringt dem nächsten nen engineer bei, fetch „nur für dieses“ ein his. Ichhätte mich für einem langweiligen Katalog entschieden, damit die Deny-Liste Der Punkt wird.
Die Kosten: Du kannst diesen Server nicht dazu benützen, „Arbeit zu erledigen“. Das ist wie gewollt. Ausführung ist ein anderer Kontract, with Identität.
MIT. Copyright (c) 2026 Bruno CarValho de Aquino.
Explain why a named capability is refused. Use this instead of asking the server to grow a shell, HTTP client, or secret reader.
| Name | Required | Description | Default |
|---|---|---|---|
| capability | Yes | A capability from the published deny-list |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations present, the description carries the full burden of behavioral disclosure. It clearly states the tool's purpose but does not mention side effects, permissions, or that it is a read-only operation. The phrase 'refused' implies it is explanatory, but the description does not explicitly say whether it executes anything or how it behaves beyond returning an explanation. This is adequate but not rich; a 3 reflects the absence of contradictions balanced against incomplete behavioral detail.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is two sentences with zero redundancy. The primary purpose is front-loaded, and the usage guidance follows immediately. Every word earns its place without padding.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a simple tool with one enum-constrained parameter and no output schema, the description provides sufficient context: it explains what it does and when to prefer it over requesting capabilities. It does not describe the return format or potential errors, but given the simplicity and the absence of an output schema, this is a minor gap. Completeness is high for the tool's complexity.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The input schema provides 100% coverage: the single parameter 'capability' has an enum list and a description that fully defines it as 'A capability from the published deny-list.' The description adds no extra semantics beyond referring to a 'named capability,' which is already covered by the schema. Given high schema coverage, the baseline of 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description states a clear verb-resource purpose: 'Explain why a named capability is refused.' It also distinguishes itself from asking the server to grow a shell, HTTP client, or secret reader, which positions it as a diagnostic tool rather than a capability-granting one. However, it does not explicitly name the sibling tools (list_catalog, lookup_api, etc.) or contrast with them, so some differentiation is left implicit.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
It provides explicit guidance on when to use this tool: 'Use this instead of asking the server to grow a shell, HTTP client, or secret reader.' This tells the agent that whenever it would consider requesting such capabilities, it should instead call explain_deny. It does not mention the sibling tools or give extensive exclusion criteria, but the core use case is clearly stated.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Return one operation from a cataloged API. Method and path must match the published spec exactly. This describes the operation; it does not invoke it.
| Name | Required | Description | Default |
|---|---|---|---|
| path | Yes | Exact OpenAPI path template, for example /orders/{orderId} | |
| apiId | Yes | ||
| method | Yes |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden. It discloses an important trait: the operation is not invoked, indicating a read-only, side-effect-free behavior. However, it does not mention error behavior (e.g., what happens on no match) or return format details, so transparency is partial. The explicit 'does not invoke' is valuable but not comprehensive.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two sentences deliver the core purpose, a constraint, and a crucial non-invocation note — no filler. The main action is front-loaded, and every clause earns its place. It is efficiently structured for quick comprehension.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
As a retrieval tool with no output schema, the description should at least indicate what structure the 'operation' takes or what happens when no match is found. It says it 'returns one operation' but does not describe the return object or error cases. Given the sibling tools and the absence of an output schema, the description is under-specified for an agent to know exactly what to expect or how to handle failures.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is only 33% (only 'path' has a description). The description adds meaning for 'method' and 'path' by stating they must match the published spec exactly, but it never explains 'apiId' — what it represents or how to obtain it. Thus, two of three parameters get some semantics, but the most opaque one remains undocumented, and the tool text does not fully compensate for the low schema coverage.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description states a clear action ('Return one operation') and resource ('from a cataloged API'), and distinguishes itself by explicitly noting it 'describes the operation; it does not invoke it.' This sets it apart from tools that might execute API calls and makes its purpose unambiguous.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
It conveys a prerequisite ('Method and path must match the published spec exactly') and a key differentiator ('does not invoke it'), but it does not explicitly compare with sibling tools like list_catalog or inspect_contract. The context of when to choose this over alternatives is implied rather than stated, so some guidance exists but lacks explicit routing.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Return the tool manifest, resource manifest, deny-list ids, and a statement of what this server is not.
| Name | Required | Description | Default |
|---|---|---|---|
No parameters | |||
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description must carry the full behavioral burden. It discloses that the tool returns manifests, deny-list ids, and a statement of what the server is not, indicating a read-only inspection. However, it doesn't mention any potential side effects, resource costs, or error behavior. For a simple read-only tool this is adequate but not rich.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single sentence that directly states what is returned. No filler, every word earns its place, and the key outputs are front-loaded. This is appropriately concise for the tool's simplicity.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a parameterless inspection tool with no output schema, the description covers the essential return values. It doesn't explain what 'tool manifest' or 'resource manifest' mean, but that may be domain-specific. It also doesn't clarify when to choose this over siblings, but given the tool's narrow scope, it's relatively complete.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The tool has zero parameters, so there is nothing for the description to explain. The baseline for 0 parameters is 4, and the description doesn't need to compensate for any schema gaps. The tool is straightforward in that regard.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description uses a clear verb ('Return') and specifies the resource (contract information: tool manifest, resource manifest, deny-list ids). It is specific about what is returned, but it doesn't explicitly contrast with sibling tools like list_catalog or explain_deny, leaving some ambiguity about what makes this unique.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description implies when to use it (for inspecting the server's contract) but doesn't state explicit conditions or exclusions relative to the siblings. It doesn't say 'use this when you need an overview' or 'don't use this for looking up specific operations'. Context is somewhat clear but not fully articulated.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
List the static OpenAPI catalog entries published with this server. Returns id, owner, lifecycle, classification, and operation count. No network.
| Name | Required | Description | Default |
|---|---|---|---|
No parameters | |||
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It discloses the return fields (id, owner, lifecycle, classification, operation count) and the 'No network' behavior, which is valuable context. It does not mention potential staleness or failure modes, but for a simple list these are minor omissions.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two sentences with zero waste. The verb and resource are front-loaded, followed by return fields and a key behavioral note. Every clause earns its place.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
The tool is simple (no params, no output schema), and the description fully explains what it does and what it returns. Sibling tools exist but differentiation is handled by purpose clarity. Nothing essential is missing for an agent to invoke it correctly.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The tool has zero parameters, so schema coverage is trivially 100%. Per calibration, a baseline of 4 applies. The description adds nothing parameter-related because none exist, which is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the verb 'List' and the resource 'static OpenAPI catalog entries published with this server', distinguishing it from siblings like lookup_api (single lookup) and get_operation (specific operation). The scope is explicit and unambiguous.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description notes 'No network' implying a fast, static listing, but does not explicitly say when to use this vs alternatives such as lookup_api. It offers no explicit exclusions or conditions, but the purpose is self-evident enough that an agent can infer suitability for overview retrieval.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Return one imported OpenAPI document by catalog id (orders, identity, billing). Rejects unknown ids. Does not fetch URLs from the spec.
| Name | Required | Description | Default |
|---|---|---|---|
| apiId | Yes | Catalog id, for example orders |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden of behavioral disclosure. It reveals two important traits: it rejects unknown ids (error behavior) and does not fetch URLs from the spec (avoiding network side-effects). Even without a return format specification, these disclosures cover the key operational concerns an agent would have.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is two short sentences, front-loaded with the core action and resource. The second sentence delivers two high-value constraints efficiently. There is zero filler; every word earns its place.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a simple single-parameter lookup with no output schema and no annotations, the description covers the essential purpose, error handling, and a limitation. It does not describe the return structure (e.g., raw JSON vs. parsed object), but that is a minor gap given the simplicity and the explicit scope of the tool. Overall, an agent can confidently invoke it.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The input schema already documents apiId with a pattern and example, achieving 100% coverage. The description adds concrete catalog id examples (orders, identity, billing) that go beyond the schema's single example, enriching the parameter's semantic meaning and helping the agent select valid values. This justifies a score above the baseline 3.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the verb 'Return' and the resource 'imported OpenAPI document' with a specific identifier (catalog id). It also gives concrete examples (orders, identity, billing) and implicitly differentiates from siblings like list_catalog (which lists) and get_operation (which fetches a specific operation). The purpose is unambiguous.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
It provides practical usage guidance by stating that unknown ids are rejected (so the agent knows to validate against the catalog) and that it does not fetch URLs from the spec (clarifying a limitation). It does not explicitly name alternatives, but the examples and behavior imply it is for looking up a single document by id, which is sufficient for most agents to route correctly.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
v1.0.0explain_denyget_operationinspect_contractlist_cataloglookup_apiScored across 5 tools
Each tool has a completely distinct purpose: listing catalogs, fetching a specific API document, retrieving a single operation, inspecting the server contract, and explaining deny behavior. No overlap or ambiguity exists.
All tool names follow a consistent lowercase verb_noun pattern (list_catalog, lookup_api, get_operation, inspect_contract, explain_deny), making the surface predictable and easy to navigate.
Five tools is precisely scoped for a read-only reference server. Each tool fills a necessary role without redundancy, and the count is neither too sparse nor overloaded for the stated purpose.
The tool set covers the full lifecycle for exploring static OpenAPI catalogs: listing, retrieving documents, drilling into operations, inspecting the server contract, and understanding denied capabilities. No apparent dead ends or missing operations for its domain.
Guarded MCP server for agent-readable business truth, provenance, readiness, and discovery.
Governed data discovery, exact queries, decisions, simulations, and runtime utilities over MCP.
Discover and inspect public Runx skills before installing them. This read-only hosted MCP exposes search_skills and get_skill. The Apache-2.0 Rust runtime executes skills locally with scoped authority, approval gates and signed receipts. Docs: https://runx.ai/docs/mcp.
Governed company knowledge over MCP. Access by contract for authorized tenants.
