tenable-activity-mcp
tenable-activity-mcp
Un servidor MCP que expone el registro de auditoría/actividad de Tenable Vulnerability Management (GET /audit-log/v1/events) como un pequeño conjunto de herramientas, para que cualquier cliente MCP pueda preguntar sobre la actividad de la plataforma, el uso de claves API y comportamientos anómalos bajo demanda.
El servidor hace el análisis. El conteo, la agrupación, los cálculos de tasas y las comparaciones de umbrales se realizan en Python; las herramientas devuelven resultados estructurados y finales (failure_rate_pct, by_actor, findings con razonamiento) en lugar de volcar eventos sin procesar para que el modelo los sume.
Lo que te ofrece
Herramienta | Propósito |
| Flujo de eventos para una ventana, con filtros de actor/acción. La paginación se sigue automáticamente; devuelve un |
| Resumen determinista para una ventana: recuentos por actor, acción, tipo CRUD y tipo de acceso, además de tasas de fallo/anónimo. |
| Solo actividad impulsada por claves API, agrupada por actor: desglose de acciones, IPs de origen distintas, primera/última vez visto. |
| Compara una ventana con la línea base almacenada de cada actor. Señala nuevos actores, picos de volumen, IPs de origen no vistas, ráfagas de eventos fallidos, tasas de fallo sostenidas, picos fuera de horario y acciones nunca antes vistas, cada uno con evidencia y una frase de razonamiento. |
| La imagen completa de un actor: rol (mejor esfuerzo), desglose de acciones de todos los tiempos, tipos de acceso, cada IP de origen vista. |
| Aprobado/fallido sobre si las claves configuradas pueden realmente leer el registro de auditoría, con texto de remediación. |
Propiedades de seguridad que vale la pena conocer:
Nunca se devuelve nada que parezca una credencial. Los valores de campos cuyos nombres de clave sugieran un secreto (
secret_key,api_key,token,password, ...) o cuyo valor parezca material de clave de Tenable se enmascaran a sus últimos 4 caracteres.La paginación está limitada a 20 páginas / 100k eventos por llamada de herramienta; alcanzar el límite se informa explícitamente junto con el cursor necesario para continuar.
Los 429 retroceden usando el encabezado
X-RateLimit-Reset(el endpoint no envíaRetry-After), con retroceso exponencial y un techo de reintentos.
Related MCP server: tenable-mcp-server
Requisitos
Python 3.11+
Claves API de Tenable VM cuyo propietario pueda leer el registro de auditoría
Rol / permisos de Tenable
Leer audit-log/v1/events requiere el rol Administrador, o un rol personalizado con permiso explícito de lectura del registro de auditoría, en el usuario que posee las claves API. Cualquier cosa menos obtiene HTTP 403; check_permission_prereqs informa eso en lenguaje claro.
Genera claves en Tenable VM bajo Configuración → Mi cuenta → Claves API. Las claves heredan los permisos del usuario que las creó.
get_actor_profile además intenta resolver el rol de un actor desde el directorio de usuarios. Si las claves no pueden listar usuarios, el perfil aún se devuelve, solo que sin la etiqueta de rol.
Configuración
uv sync --extra devLuego copia .env.example a .env y completa tus claves:
cp .env.example .envVerifica las credenciales y permisos antes de conectarlo a un cliente:
uv run python -c "from dotenv import load_dotenv; load_dotenv(); from src.server import check_permission_prereqs; print(check_permission_prereqs())"Ejecuta el servidor directamente (habla MCP sobre stdio, así que simplemente se quedará esperando a un cliente; ese es el comportamiento correcto):
uv run python -m src.serverConectando un cliente
Usa la ruta absoluta a tu clon en la configuración a continuación. Para imprimirla, ejecuta pwd desde la raíz del repositorio en macOS/Linux, o (Get-Location).Path en PowerShell.
Claude Desktop
Edita claude_desktop_config.json:
macOS:
~/Library/Application Support/Claude/claude_desktop_config.jsonWindows:
%APPDATA%\Claude\claude_desktop_config.json
{
"mcpServers": {
"tenable-activity": {
"command": "uv",
"args": [
"--directory",
"C:\\path\\to\\tenable-activity-mcp",
"run",
"python",
"-m",
"src.server"
],
"env": {
"TENABLE_ACCESS_KEY": "your_access_key",
"TENABLE_SECRET_KEY": "your_secret_key",
"TENABLE_MCP_BASE_URL": "https://cloud.tenable.com"
}
}
}
}Reinicia Claude Desktop después. En macOS/Linux usa una ruta POSIX (/Users/you/tenable-activity-mcp).
Si uv no está en el PATH del lanzador, usa su ruta absoluta (which uv / (Get-Command uv).Source) como command.
Claude Code
claude mcp add tenable-activity --env TENABLE_ACCESS_KEY=your_access_key --env TENABLE_SECRET_KEY=your_secret_key -- uv --directory /absolute/path/to/tenable-activity-mcp run python -m src.serverO agrega el mismo bloque de arriba a un .mcp.json a nivel de proyecto.
Las credenciales pasadas mediante env tienen prioridad sobre .env; el archivo .env es una conveniencia para desarrollo local, y cualquiera de los dos mecanismos funciona.
Preguntas de ejemplo para hacer una vez conectado
"Comprueba si mis credenciales de Tenable pueden leer el registro de auditoría."
"Resume la actividad de la plataforma Tenable de los últimos 7 días: ¿quién fue más activo y cuál es la tasa de fallos?"
"¿Qué claves API se usaron contra Tenable en los últimos 30 días y desde qué IPs de origen?"
"Busca anomalías en la actividad de Tenable de los últimos 3 días contra una línea base de 30 días, y explica cualquier cosa que señales."
"Muéstrame todo lo que el actor 00000000-1111-4222-8333-444444444444 ha hecho alguna vez: acciones, tipos de acceso e IPs."
Cómo funciona la detección de anomalías
detect_anomalies necesita historial para comparar, que vive en un archivo SQLite local (state.db, creado automáticamente):
Si las líneas base almacenadas son más antiguas que
BASELINE_REFRESH_MAX_AGE_HOURS(12), el servidor obtiene losbaseline_daysinmediatamente anteriores a tu ventana y recalcula los promedios por actor, IPs conocidas, acciones conocidas y un histograma de hora del día.Tu ventana se obtiene y se compara contra esas líneas base.
Los eventos en la ventana analizada no se incorporan a la línea base, por lo que volver a ejecutar la misma ventana devuelve los mismos hallazgos.
Cada umbral es una constante nombrada al inicio de src/anomaly.py y se repite en cada resultado bajo thresholds:
Constante | Predeterminado | Significado |
|
| Los eventos/día de la ventana deben exceder este múltiplo del promedio de la línea base |
|
| Mínimo antes de que un pico pueda señalarse en absoluto |
|
| Cuán recientemente debe haberse visto una IP para contar como "conocida" |
|
| Disparador de agrupación de fallos |
|
| Disparador de tasa de fallo sostenida (sobre al menos 10 eventos) |
|
| Banda fuera de horario |
|
| La proporción fuera de horario debe exceder este múltiplo de la proporción de la línea base del actor |
Las líneas base son por actor, por lo que una cuenta de servicio que legítimamente ejecuta 500 escaneos al día no se señala por hacer exactamente eso.
Estructura
src/
server.py MCP entrypoint (FastMCP-style) + the six tool definitions
tenable_client.py Auth, filter building, cursor pagination, 429 backoff, typed errors
classifier.py API-key vs UI/session tagging, IP extraction, redaction, rollups
anomaly.py Thresholds and the individual anomaly checks
state.py SQLite: cursors, accumulated actor history, computed baselines
tests/
test_pagination.py test_classifier.py test_anomaly.pyLa dirección de dependencias es unidireccional: server → {anomaly, classifier, state} → tenable_client.
Pruebas
Tres niveles, en el orden en que deberías ejecutarlos.
1. Pruebas unitarias (sin credenciales, sin red)
uv run pytest -q105 pruebas que cubren manejo de paginación/cursor, retroceso de límite de tasa, clasificación de clave API vs sesión, redacción y cada umbral de anomalía. Cada respuesta de API se simula a través de un transporte stub, por lo que la suite nunca toca un tenant en vivo.
2. Extremo a extremo sin conexión (sin credenciales, sin red)
uv run python scripts/smoke_local.pyEjecuta las seis herramientas contra un Tenable falso con guion (un mes de línea base tranquilo, luego una noche ruidosa desde una IP nueva) y verifica los resultados: anomalías señaladas, secretos plantados redactados, entrada incorrecta devuelta como error estructurado en lugar de excepción. Sale con código no cero en cualquier fallo, por lo que funciona como puerta de pre-commit o CI.
3. Verificación en vivo contra tu tenant (solo lectura)
Con .env completado:
uv run python scripts/live_check.py 7Primero verifica los permisos del registro de auditoría y se detiene con texto de remediación si son incorrectos, luego imprime un resumen real, desglose de uso de claves API, hallazgos de anomalías y el perfil del actor más ocupado de los últimos N días (predeterminado 7). Todas las llamadas son GET; no se escribe nada en Tenable.
4. A través de un cliente MCP
Cualquier cliente MCP funciona. Para probar las herramientas interactivamente sin un cliente de chat:
npx @modelcontextprotocol/inspector uv --directory . run python -m src.serverO conéctalo a Claude Desktop / Claude Code (arriba) y haz una de las preguntas de ejemplo. check_permission_prereqs es la primera llamada correcta: confirma que el servidor se inició, encontró sus credenciales y puede llegar al registro de auditoría.
Inspeccionando el estado local
uv run python -c "from src.state import StateStore; print(StateStore().stats())"Elimina state.db para restablecer las líneas base; la próxima llamada a detect_anomalies las reconstruye.
Limitaciones conocidas
Requiere el rol de Administrador. La lectura de
audit-log/v1/eventsrequiere el rol de Administrador, o un rol personalizado con permiso explícito de lectura del registro de auditoría, en el usuario propietario de las claves de API. Cualquier permiso inferior devuelve HTTP 403. Ejecutecheck_permission_prereqsprimero: informa exactamente de esto, con texto de corrección.La detección de anomalías necesita historial antes de ser útil. La primera llamada a
detect_anomaliescontra unstate.dbnuevo construye las líneas base a partir de los 30 días anteriores a su ventana y luego compara contra ellas. Los actores con poca o ninguna actividad previa se marcan comonew_actor, por lo que las primeras ejecuciones son más ruidosas que las posteriores.La resolución de roles es de mejor esfuerzo.
get_actor_profileintenta resolver el rol de Tenable de un actor desde el directorio de usuarios. Si las claves no pueden listar usuarios, el perfil se devuelve igualmente, solo que sin la etiqueta del rol.La detección de horas no laborables usa una banda UTC fija. La ventana de horas no laborables es 20:00-06:00 UTC y no se ajusta a la zona horaria de trabajo del inquilino. Los equipos distribuidos verán hallazgos de horas no laborables que son simplemente la mañana laboral de otra región.
Las líneas base son locales a la máquina que ejecuta el servidor.
state.dbno se comparte entre instalaciones, por lo que dos operadores que ejecutan sus propias copias construyen líneas base independientes y pueden llegar a conclusiones diferentes sobre la misma ventana.Las ventanas amplias devuelven resultados parciales por diseño. Una llamada de herramienta sigue como máximo 20 páginas / 100.000 eventos. Alcanzar ese límite se informa explícitamente junto con el
next_tokennecesario para reanudar, por lo que nunca es una truncación silenciosa, pero una ventana muy grande requiere varias llamadas.Solo los primeros 1.000 eventos se devuelven en línea.
list_activity_eventslimita el arrayeventsen línea a 1.000 y estableceinline_truncatedcuando lo hace. El bloquesummarysigue cubriendo todos los eventos recuperados, por lo que los números agregados permanecen correctos incluso cuando la lista en línea se recorta.get_actor_profilemira hacia atrás 365 días como máximo, y no puede ver más atrás de lo que el propio registro de auditoría conserva.
Notas
Desarrollado con
mcp==2.0.0, donde el SDK renombróFastMCPaMCPServer.server.pyimporta el nombre que proporcione el SDK instalado, por lo que también funciona enmcp1.x.La recuperación de eventos pasa por la sesión
TenableIOde pyTenable (audit_log.events(..., return_json=True)), que mantiene el manejo de autenticación y conexión en la biblioteca mantenida, dejando el cursorpagination.nextvisible para nosotros. Si pyTenable no está disponible, un transporte equivalente conrequestsque usa la cabeceraX-ApiKeys: accessKey=...;secretKey=...toma el relevo.Las marcas de tiempo están en UTC en todas partes, incluida la banda de horas no laborables.
state.dbacumula el historial por actor. Elimínelo para restablecer todas las líneas base; la siguiente llamada adetect_anomalieslas reconstruye.
Available Tools
6 toolscheck_permission_prereqsA
Verify the configured API keys can actually read the audit log.
Makes one minimal audit-log request and reports pass/fail with a plain explanation and remediation steps. Run this first when another tool returns an authentication or permission error. No secret material is echoed - the access key is shown with only its last 4 characters.
Returns:
A dict with ok, a human-readable message, remediation when
failing, plus configuration and local-state diagnostics.
| Name | Required | Description | Default |
|---|---|---|---|
No parameters | |||
Output Schema
| Name | Required | Description |
|---|---|---|
No output parameters | ||
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description fully discloses behavior: it makes exactly one minimal audit-log request, reports pass/fail with a plain explanation plus remediation steps, and never echoes secret material (the access key shows only the last 4 characters). This goes well beyond a bare operation statement and gives the agent confidence about side effects and output safety.
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 purpose is front-loaded in the first sentence, and the remaining sentences carry useful information about behavior, triggering, and secret handling. The 'Returns' section slightly overlaps with the provided output schema, but it only lists the key dictionary fields and is not padded. Overall it is tightly written for the information it needs to convey.
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 tool with no parameters and a full output schema, the description covers everything an agent needs: what is checked, when to run it, what side effects occur (one request, no secret disclosure), and what the result looks like. There are no missing pieces that would cause an agent to misuses the tool.
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 the baseline is 4. The description does not need to explain parameter meaning, and the empty input schema leaves nothing ambiguous; the description instead focuses on the output, which is appropriate here.
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 opens with a specific verb and resource: 'Verify the configured API keys can actually read the audit log,' which clearly states what the tool does. It also distinguishes itself from the sibling data-retrieval tools (list_activity_events, summarize_activity, etc.) by positioning this as a diagnostic preflight check rather than an analytics operation.
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 gives an explicit trigger condition: 'Run this first when another tool returns an authentication or permission error.' This is clear contextual guidance, but it does not mention when not to use it or name alternative tools—though no sibling performs the same diagnostic role, so exclusions are not necessary.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
detect_anomaliesA
Compare a window against each actor's stored baseline and flag outliers.
Checks run: previously unseen actor, event volume above SPIKE_MULTIPLIER x
the actor's historical daily average, source IPs absent from the baseline
lookback, failed-event bursts, sustained high failure rate, off-hours
activity spikes, and never-before-seen action types. Every finding includes
the observed value, the threshold crossed, and a reasoning sentence.
Baselines live in the local SQLite state file and are refreshed from the period immediately preceding the window when they are stale. Events in the analysed window itself are not folded into the baseline, so re-running the same window yields the same findings.
Args: date_from: Start of the window under investigation, ISO-8601. date_to: End of the window under investigation, ISO-8601. baseline_days: Days of history preceding the window to baseline against.
Returns:
A dict with findings (severity-ordered, each with evidence and
reasoning), findings_by_type/findings_by_severity counts, and
the active thresholds.
| Name | Required | Description | Default |
|---|---|---|---|
| date_to | Yes | ||
| date_from | Yes | ||
| baseline_days | No |
Output Schema
| Name | Required | Description |
|---|---|---|
No output parameters | ||
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries full burden and covers side effects (baseline refresh from local SQLite when stale), idempotence (analyzed window not folded into baseline), and output guarantees (evidence, reasoning, severity ordering). This exceeds what schema alone could convey.
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 definition is dense but every sentence adds necessary operational detail; purpose is front-loaded, checks are grouped, and Args/Returns are clearly structured. No filler or repetition.
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 tool with no annotations and moderate input complexity, it explains inputs, output shape, baseline mechanics, staleness handling, and idempotence. An agent has enough to select and call it correctly without further discovery.
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 0%, but the Args section documents all three parameters with semantic meaning: ISO-8601 window bounds and baseline history days. This fully compensates for the absent schema descriptions.
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?
Opens with a specific verb-resource pair ('Compare a window against each actor's stored baseline') and an enumerated list of anomaly checks that distinguishes this from sibling event-listing/summary tools. The resource and behavior are unmistakable.
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 intended investigation scenario is clear: detect baseline deviations in a date window using prior history. It does not explicitly name alternatives or when-not-to-use, but the detailed scope leaves little ambiguity about when this tool applies.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
get_actor_profileA
Full historical view of one actor: roles, actions, access types, IPs.
Combines a fresh audit-log fetch for the actor with everything previously persisted in the local state database, so IPs and actions seen in earlier sessions still show up. The Tenable role is resolved on a best-effort basis from the user directory and is omitted when the API keys cannot list users.
Args:
actor_id: The actor UUID (as it appears in actor.id on events).
lookback_days: How far back to fetch fresh events for this actor.
Returns:
A dict with identity, recent_activity (rollup over the lookback
window), lifetime (accumulated state: all IPs, all actions, all
access types, first/last seen) and pagination.
| Name | Required | Description | Default |
|---|---|---|---|
| actor_id | Yes | ||
| lookback_days | No |
Output Schema
| Name | Required | Description |
|---|---|---|
No output parameters | ||
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations available, the description carries the behavioral burden and does so well. It discloses that data combines a fresh audit-log fetch with persisted local state, explains best-effort role resolution, and notes when role data is omitted. This is substantive behavioral context beyond a simple summary.
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 well structured with a one-sentence summary, a clear behavioral explanation, and separate Args/Returns sections. It is appropriately detailed for the tool's complexity without padding, and each sentence adds useful information.
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?
Given the tool's moderate complexity, zero annotation coverage, and 0% schema description coverage, the description supplies everything needed: what the profile contains, how data is combined, parameter semantics, and return structure. The output schema also exists, but the description goes beyond it by explaining the lifetime/recent_activity distinction.
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 description coverage is 0%, so the description fully compensates. actor_id is explained as the actor UUID as seen in actor.id, and lookback_days is defined as how far back to fetch fresh events. Both parameters receive meaningful semantic detail not present in the schema.
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 opens with 'Full historical view of one actor: roles, actions, access types, IPs', which names a specific resource and scope. It clearly distinguishes this from siblings like list_activity_events or summarize_activity by emphasizing the per-actor, history-combining nature.
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?
Usage context is implied rather than explicit: the tool is for obtaining a comprehensive actor profile that merges fresh data with persisted state. It does not explicitly state when to prefer this over sibling tools or provide exclusions, so an agent must infer the right selection.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
get_api_key_usageA
Report API-key-driven activity per actor (UI/session activity excluded).
Events are classified as API-key driven using the audit event's access/auth-method field, falling back to user-agent shape (scripted client vs browser). Each actor gets an action breakdown, distinct source IPs, and first/last seen timestamps - all pre-aggregated.
Args: actor_id: Optional actor UUID. Omit to cover every actor with API-key activity in the window. date_from: Start of the window, ISO-8601. Defaults to 30 days ago. date_to: End of the window, ISO-8601. Defaults to now.
Returns:
A dict with actors (per-actor API-key usage profiles), an
access_type_totals breakdown for context, and coverage metadata.
| Name | Required | Description | Default |
|---|---|---|---|
| date_to | No | ||
| actor_id | No | ||
| date_from | No |
Output Schema
| Name | Required | Description |
|---|---|---|
No output parameters | ||
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the burden of explaining behavior, and it does so well: it discloses the classification method (audit access/auth-method with user-agent fallback), that results are pre-aggregated, and what per-actor fields are returned. It does not mention permissions or rate limits, but 'Report' and 'Returns' strongly imply a safe, read-only operation.
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 front-loaded with a clear one-sentence summary, followed by a concise classification note and clearly labeled Args and Returns sections. Every sentence adds useful information and there is no filler or redundant restating of the tool name.
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 report tool with three optional parameters and an output schema, the description covers the core behavior, defaults, and return shape sufficiently. Minor gaps remain, such as date-boundary inclusivity and explicit guidance about which sibling tools to use instead, but nothing essential is missing for invoking 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?
Schema description coverage is 0%, so the description must compensate, and it does. All three parameters are explained with semantics beyond the bare schema: actor_id is an optional UUID, date_from defaults to 30 days ago, and date_to defaults to now, with ISO-8601 format specified.
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 specific verb and resource: 'Report API-key-driven activity per actor' and explicitly excludes UI/session activity. It further clarifies the output (per-actor action breakdown, distinct source IPs, first/last seen timestamps), which distinguishes this tool from the sibling activity tools even without naming them.
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 intended use is clear: this tool is for API-key-driven activity reporting, and the description explicitly notes that UI/session activity is excluded. It also explains the effect of omitting actor_id, but it does not explicitly name alternative sibling tools for when this tool should not be used.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
list_activity_eventsA
List Tenable audit-log events for a date range, with optional filters.
Pagination is handled internally (the next cursor is followed
automatically) up to a safety cap of 20 pages / 100k events per call; if the
cap is hit, pagination.next_token is returned so the next call resumes
exactly where this one stopped. Every event is normalised, tagged with an
access type (API key vs UI session), and has credential-looking field values
redacted to their last 4 characters.
Args:
date_from: Start of the window, ISO-8601 (e.g. "2024-01-01" or
"2024-01-01T00:00:00Z"). Inclusive.
date_to: End of the window, ISO-8601. Inclusive.
actor_id: Optional actor UUID to filter on (actor_id.eq).
action: Optional exact action name, e.g. "user.create" (action.eq).
limit: Page size sent to the API (1-5000).
next_token: Opaque cursor from a previous call, to resume pagination.
Returns:
A dict with events (classified, redacted), a summary rollup of
those events, and a pagination block.
| Name | Required | Description | Default |
|---|---|---|---|
| limit | No | ||
| action | No | ||
| date_to | Yes | ||
| actor_id | No | ||
| date_from | Yes | ||
| next_token | No |
Output Schema
| Name | Required | Description |
|---|---|---|
No output parameters | ||
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full behavioral burden and does so exceptionally well. It discloses internal pagination with a 20-page/100k-event cap, resume behavior via next_token, normalization of events, access-type tagging, and redaction of credential-looking fields. This is far beyond what a minimal description would provide.
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 information-dense yet well-structured: purpose first, then behavioral caveats, then parameter breakdown, then return structure. Every sentence adds value, and the length is justified by the number of parameters and the pagination/redaction behaviors that need explanation.
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 6-parameter tool with no annotations, the description covers use case, filtering, pagination limits, resume semantics, data normalization, redaction, and return shape. The optional filters and cap behavior are fully explained, leaving no critical gap for an agent attempting to invoke the tool 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?
Schema description coverage is 0%, but the description compensates completely by explaining every parameter: date format and inclusivity, optional filters with their eq semantics, the exact action example, limit range, and the opaque next_token cursor. An agent can correctly populate all six arguments without needing extra documentation.
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 begins with a specific verb ('List') and resource ('Tenable audit-log events'), and states the scope ('for a date range') with optional filters. This clearly distinguishes it from sibling tools like summarize_activity and detect_anomalies, so an agent knows exactly what this tool retrieves.
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 makes the core use case clear: retrieve audit-log events within a date range, optionally filtered by actor or action. It does not explicitly name sibling alternatives or provide when-not-to-use guidance, but the event-listing purpose is unambiguous and the filter details help an agent choose appropriately.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
summarize_activityA
Summarise all audit-log activity in a window (counts computed in Python).
Returns event counts by actor, by action, by CRUD type and by access type, plus failure and anonymous rates - all pre-computed. Use these numbers directly; do not re-derive them from raw events.
Args: date_from: Start of the window, ISO-8601. Inclusive. date_to: End of the window, ISO-8601. Inclusive.
Returns:
A dict with a summary block (total_events, by_actor,
by_action, by_crud, by_access_type, failure_rate_pct,
top_failed_actions) and a pagination block describing coverage.
| Name | Required | Description | Default |
|---|---|---|---|
| date_to | Yes | ||
| date_from | Yes |
Output Schema
| Name | Required | Description |
|---|---|---|
No output parameters | ||
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. It discloses that counts are pre-computed in Python, that date boundaries are inclusive, and it exposes the exact return structure with summary and pagination blocks. It does not mention permissions, error behavior, or timezone assumptions, but for a read-only aggregation these are not critical.
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 well-organized with a concise purpose line, a usage warning, and clear Args/Returns sections. There is slight redundancy where the prose mention of 'Returns event counts...' is later repeated as a structured returns block, but the text is otherwise efficient and front-loaded.
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 two-parameter aggregation tool with an output schema present, the description covers purpose, parameter semantics, and return keys sufficiently. It lacks an explicit when-to-use-versus-siblings statement and has no annotation safety profile, but the core invocation details are complete enough for an agent to call 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 input schema provides only bare string properties with 0% coverage. The description compensates fully by defining date_from as 'Start of the window, ISO-8601. Inclusive' and date_to as 'End of the window, ISO-8601. Inclusive', adding format, semantic role, and boundary inclusivity to both parameters.
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 specific verb and resource: 'Summarise all audit-log activity in a window', and enumerates the output dimensions (by actor, action, CRUD, access type, failure and anonymous rates). This clearly frames the tool as an aggregation over raw events and distinguishes it from siblings like list_activity_events or get_actor_profile.
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?
Provides a strong usage directive: 'Use these numbers directly; do not re-derive them from raw events.' This tells the agent to rely on pre-computed counts rather than computing from raw event lists, which is clear contextual guidance. It does not explicitly name alternative tools or exclusion conditions, but the implied comparison to raw event access is present.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Tool Schema Changelog
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
6 tool updates
v0.1.0- First observed
check_permission_prereqs - First observed
detect_anomalies - First observed
get_actor_profile - First observed
get_api_key_usage - First observed
list_activity_events - First observed
summarize_activity
TDQS
Scored across 6 tools
Each tool targets a clearly different concern: raw event listing, summary rollups, API-key-specific usage, anomaly detection, actor profiling, and prerequisite checks. Even the two aggregation tools (summarize_activity and get_api_key_usage) are separated by access-type scope, and their descriptions reinforce the distinction.
All tool names follow a consistent snake_case verb_noun pattern: list_activity_events, summarize_activity, get_api_key_usage, detect_anomalies, get_actor_profile, check_permission_prereqs. The verbs clearly signal the action and the objects clearly signal the resource or concern, making the set predictable and easy to navigate.
Six tools is well-scoped for an audit-log activity server: two raw/aggregate views, two analysis-focused tools, one deep-dive tool, and one operational prerequisite check. Each tool earns its place without redundancy or bloat.
The tool surface covers the full audit-monitoring lifecycle: listing raw events, summarizing them, isolating API-key usage, detecting anomalies, profiling individual actors, and verifying access prerequisites. The automatic pagination and baseline handling close potential dead ends, so an agent can move from raw data to insight without missing critical operations.
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