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Getting Started

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Lasse Nielsen edited this page May 29, 2026 · 2 revisions

Getting Started

This tutorial walks you through a first session with the servicenow-platform-mcp server. You have it installed and connected to an MCP client; now you want to do useful things. Each step builds on the last - by the end you will have queried records, inspected schema, written safely, resolved choice labels, and run an investigation.

Prerequisites

  • Server installed and running (see INSTALL.md)
  • Credentials pointing at a dev or sandbox ServiceNow instance
  • MCP_TOOL_PACKAGE set to full (the default)

1. Confirm the Server Is Up

Call list_tool_packages with no arguments.

This tool is special: it bypasses @tool_handler entirely and returns raw JSON - no status field, no correlation_id, no error envelope. It is always registered regardless of your active package.

Expected output:

{
  "full": ["query", "build_query", "describe", "record_read", "record_write", "attachment", "investigate", "resolve_choice", "service_catalog", "audit", "flow"],
  "readonly": ["query", "describe", "record_read", "attachment", "investigate", "resolve_choice", "audit", "flow"],
  "core_readonly": ["query", "describe", "attachment"],
  "none": []
}

If your MCP client shows only list_tool_packages and nothing else, your MCP_TOOL_PACKAGE value is none or does not match a valid preset or comma-separated group list.

2. Inspect a Table

Call describe with only table:

{ "table": "incident" }

When action is omitted (or empty string), describe runs the default field-metadata flow: it queries sys_dictionary and returns each field's name, label, type, max_length, mandatory flag, read_only flag, reference_table, and choice_count.

The action parameter accepts exactly one value: "list_script_fields". Any other string - for example action: "fields" - returns the error:

Unknown describe action 'fields'. Valid actions: ['list_script_fields'].

Do not guess action names. Omit the parameter for field metadata; pass "list_script_fields" when you need the script-bearing fields on a table.

3. Query Records

Call query with:

{ "table": "incident", "limit": 5 }

The response envelope includes data (the masked records), pagination with offset, limit, and total, plus a correlation_id for tracing.

To filter, pass encoded_query using ServiceNow's encoded query syntax:

{ "table": "incident", "limit": 5, "encoded_query": "active=true^priority=1" }

The server enforces query safety: limits are capped at MAX_ROW_LIMIT (default 100), and large tables (syslog, sys_audit, sys_log_transaction, sys_email_log) require a date-bounded filter.

4. Read One Record

Take a sys_id from the query results and call record_read:

{ "table": "incident", "sys_id": "a1b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6" }

The response includes the full masked record plus script_fields - the list of script-bearing fields detected on that table via the DictionaryRegistry.

Exactly one of sys_id or name must be supplied. Passing both returns an error; passing neither also returns an error. When using name, if multiple records match the server returns an ambiguity error rather than guessing.

5. Write Safely (Preview-Then-Apply)

Writes use a two-step pattern by default.

Step 5a - Preview:

{
  "table": "incident",
  "action": "update",
  "sys_id": "a1b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6",
  "data": "{\"short_description\": \"Updated via MCP\"}"
}

Because preview defaults to True, the server does not touch ServiceNow. It fetches the current record, computes a diff, stores the payload in a single-use token store (TTL 5 minutes), and returns a preview_token along with the masked diff.

Step 5b - Apply:

{ "preview_token": "b7e4f9a2-1c3d-4e5f-8a9b-0c1d2e3f4a5b" }

Call record_apply with the preview_token parameter (not token - the parameter name is preview_token). The server consumes the token, re-validates write permissions, and executes the update. The token is single-use; replaying it returns "Invalid or expired preview token".

6. Resolve Choice Labels

Human-readable labels like "In Progress" do not match the numeric values ServiceNow stores. Call resolve_choice to map them:

{ "table": "incident", "field": "state" }

With no label parameter, this returns all known choices for that field (e.g. open=1, in_progress=2, on_hold=3, resolved=6, closed=7, canceled=8). Pass label to resolve a single value:

{ "table": "incident", "field": "state", "label": "in_progress" }

Labels are normalized: lowercase, spaces replaced with underscores.

7. Run an Investigation

The investigate tool dispatches predefined analysis playbooks. Call it with:

{
  "action": "run",
  "name": "stale_automations",
  "params": "{\"stale_days\": 90}"
}

The parameter is name (not investigation). The params value is a JSON string parsed server-side.

Three actions are available:

  • run - execute the investigation and return findings
  • explain - given an element_id (format table:sys_id), ask all registered investigations to explain that element
  • describe - list available investigations and their parameters (no platform I/O)

Seven investigations are registered: stale_automations, deprecated_apis, table_health, acl_conflicts, error_analysis, slow_transactions, performance_bottlenecks.

8. Production Safety

When SERVICENOW_ENV is set to prod or production, ALL write operations are blocked regardless of table. The server returns a serialized error envelope with the message:

Write operations are blocked in production environments

This applies to record_write, record_apply, attachment_write, and the write actions on service_catalog (ordering, cart operations). There is no override flag - the block is absolute for the environment.

Even outside production, 8 security-sensitive tables are permanently denied for writes (and reads): sys_user_has_password, oauth_credential, oauth_entity, sys_certificate, sys_ssh_key, sys_credentials, discovery_credentials, sys_user_token.

Where to Go Next

  • Tool-Reference - complete parameter and response documentation for every tool
  • Investigations - the 7 registered playbooks, their parameters, and element_id format
  • Safety-and-Policy - denied tables, field masking, query safety, and write gating in detail

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