// SCAN REPORT

Nexus Core

134 tools. 54 can modify or destroy data without limits.

8 destructive tools with no built-in limits. Policy required.

Last updated: 2 Jul 2026

54 can modify or destroy data

80 read-only

134 tools total

Community server · catalogue entry verified 02/07/2026

How to control Nexus Core ↓

TOOL MAP

What Nexus Core exposes to your agents

Read (80) Write / Execute (46) Destructive / Financial (8)

Running more than one server? Check your whole stack →

MOST DANGEROUS TOOLS

Critical Risk

The most dangerous Nexus Core tools

Destructive · High cancel_event Deleting a calendar event is an irreversible destructive action that removes data and cannot be undone by the tool itself. Destructive · Medium delete Although the action is recoverable within 30 days, moving messages to Trash is effectively a destructive operation — data is removed from its original location and inaccessible in normal flow. Destructive · High delete_contact This tool permanently removes a contact from Google Contacts. Destructive · High delete_cron_job Cron jobs are scheduled automated tasks that may be critical to system operations, backups, monitoring, or other essential functions.

54 of Nexus Core's 134 tools can modify, destroy, or commit something on every call — and an agent calls them with no built-in limits.

POLICY

How to control Nexus Core

PolicyLayer is an MCP gateway — it sits between your AI agents and Nexus Core, and nothing reaches the server without passing your rules. These are the rules we recommend:

Deny destructive operations

{
  "cancel_event": {
    "deny_if": [
      {
        "conditions": [],
        "on_deny": "Blocked by default. Requires approval."
      }
    ]
  }
}

Destructive tools should never be available to autonomous agents without human approval.

Rate limit write operations

{
  "accept_invite": {
    "limits": [
      {
        "counter": "accept_invite_per_hour",
        "window": "hour",
        "max": 30,
        "scope": "grant"
      }
    ]
  }
}

Prevents bulk unintended modifications from agents caught in loops.

Cap read operations

{
  "base64_decode": {
    "limits": [
      {
        "counter": "base64_decode_per_minute",
        "window": "minute",
        "max": 60,
        "scope": "grant"
      }
    ]
  }
}

Controls API costs and prevents retry loops from exhausting upstream rate limits.

Create a free account and register Nexus Core — nothing to install.
Add these rules — paste them, or build them visually. Tune the limits to your setup.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

ENFORCE POLICY ON NEXUS CORE →

Instant setup, no code required.

FULL CATALOGUE

All 134 Nexus Core tools

DESTRUCTIVE 8 tools

Destructive cancel_event Delete a calendar event. notify_attendees controls whether cancellation emails are sent. Destructive delete Move messages to Trash (recoverable 30 days). NOT permanent delete. Destructive delete_contact DELETE a Google contact by resourceName. Destructive delete_cron_job Permanently remove a cron job. APPROVAL-EQUIVALENT — host should gate. Destructive delete_file DELETE a single file. Refuses directories (no recursive delete). Path must validate. Destructive delete_task DELETE a task permanently. Destructive forget DELETE a memory by key. Returns whether it existed. Destructive remove_from_group Remove a contact from a group.

EXECUTE 4 tools

Execute create_cron_job Register a recurring action. schedule_expression is a standard 5-field cron string Execute fill_web_form APPROVAL-GATED: navigate to URL, fill named fields with human-like typing. Execute resume_cron_job Reactivate a paused cron job. Scoped to the calling user. Execute screenshot Navigate to URL and write a PNG screenshot to output_path (must be inside ALLOWED_ROOTS).

WRITE 42 tools

Write accept_invite Respond 'accepted' to an event invitation. Write add_label Apply a Gmail label to a message. Creates the label if it doesn't exist. Write add_signature_to_pdf Overlay a signature image on a specific page + (x,y) of a PDF. Visual overlay only — NOT cryptographic. Write add_to_group Add a contact to a group. Creates the group if it doesn't exist. Write append_to_file APPEND text to an existing or new file. Same security boundary as write_text_file. Write archive Archive: remove from INBOX (keeps the message). Write block_focus_time Create a calendar event titled label (default 'Focus') to protect the window. Write book_appointment APPROVAL-GATED: Calendly-style booking. Site-specific adapters not yet wired. Write cancel_reminder Set reminder status to 'cancelled'. Write complete_task Mark a task done. Write create_contact Create a new Google contact. groups = list of group names (resolved server-side). Write create_event Create a calendar event. start/end ISO-8601. recurring = RRULE string (e.g. 'FREQ=WEEKLY;COUNT=10'). Write create_pdf_from_template Fill a named PDF template's AcroForm fields and write to output_path. Write create_pdf_from_text Generate a PDF from text. Options: font_name, font_size, page_size ('letter'|'a4'), margin_pt. Write create_project Register a project name. (Projects emerge from tasks with that source; this is a no-op confirmation.) Write create_reminder Create a reminder. fire_at = ISO-8601 datetime. recurring optional (e.g. 'FREQ=DAILY'). Write create_task Create a task. due = ISO-8601 datetime. project stored in source column. Write decline_invite Respond 'declined' with optional note. Write draft_email Create a Gmail draft. Returns draft_id. Write extract_attachments Save all attachments of a message into save_to_path (must be an existing dir inside ALLOWED_ROOTS). Write fill_pdf_form Fill AcroForm fields in input_path PDF and save to output_path. Write forward_email Create a forwarded draft (does NOT auto-send). Use send_email to dispatch. Write generate_password Generate one or more cryptographically random passwords. Write import_vcard Bulk-import contacts from a .vcf file inside ALLOWED_ROOTS. Write journal_entry Append a journal entry. Optional mood + tags. Write mark_read Remove the UNREAD label from one or more messages. Write merge_pdfs Concatenate multiple PDFs into output_path, in order. Write move_file MOVE/RENAME a file. Both paths must validate. Refuses to overwrite an existing file at destination. Write move_to_folder Move = apply label + remove INBOX. Gmail has no real folders; labels stand in. Write qr_code Generate a QR code PNG. output_path must resolve inside ALLOWED_ROOTS. Write remember Save a fact under key. Overwrites existing entry. Optional ISO-8601 expires. Write reply_to_email Create a reply draft (does NOT auto-send). Use send_email to dispatch. Write save_decision Log an architectural / life decision. Date defaults to today (UTC). Write send_email SEND a saved draft. Approval-equivalent — Claude CLI gates. Write snooze_reminder Push next_fire_at later. until = ISO-8601 datetime. Write tentative_invite Respond 'tentative' to an event invitation. Write update_contact Modify a contact. fields keys: names (str), emails (list[str]), phones (list[str]), notes (str). Write update_event Modify event fields. Allowed: title, start, end, location, description, attendees. Write update_memory Modify the value of an existing memory. Returns not_found if key absent. Write update_reminder Modify a reminder. Allowed change keys: body, fire_at (ISO), recurrence, status. Write update_task Modify a task. Allowed change keys: title, due (ISO|null), project, priority (int), status. Write write_text_file WRITE: create or replace a text file at path. Parent must already exist inside ALLOWED_ROOTS.

READ 80 tools

Read base64_decode Decode base64 to UTF-8 string. Read base64_encode Encode string as base64 (UTF-8). Read birthday_reminders Contacts with birthdays in the next N days (Google People birthday field). Read check_conflicts Return events overlapping the proposed window. Read check_website_status HEAD-equivalent: returns HTTP status_code + ok bool. Uses full browser (cookies, JS). Read convert_units Convert a value between units. Supports distance, mass, temperature, volume, time. Read currency_convert Convert currency at live exchange rates via open.er-api.com (free, no auth). Read current_time Current time in specified IANA timezone (e.g. 'America/New_York'). UTC if omitted. Read daily_briefing Today's active reminders + pending tasks due today + overdue items. Read describe_my_access describe_my_access Read do_math Evaluate an arithmetic expression with + - / // % and parentheses. No functions, no names. Read extract_pdf_form_fields Return AcroForm field names + types for a PDF. Read fetch_url Fetch the page at URL. Returns title, visible text, html length + 5KB preview. Read file_info Stat: path, size, modified, mime type, owner uid, is_file/is_dir. Read find_contact Search contacts by name/email/phone/company substring (Google People searchContacts). Read find_emails_about Substring search across recent mail. Falls back to Gmail full-text search. Read find_file Find files by name (substring). If content=True, also greps text files for the query. Read find_free_time Find slots of duration_minutes between [start, end]. working_hours = [start_hour, end_hour], default [9,18]. Read find_journal_entries Search journal entries by content substring and/or date range [start, end] ISO dates. Read find_recurring_meetings List recurring events in the next N days. Read flip_coin Flip N coins. Read get_contact_details Full contact record by resourceName (e.g. 'people/c1234567890123'). Read hash_text Hash text with one of: md5, sha1, sha224, sha256, sha384, sha512. Read hebcal Hebrew date + parsha + holidays for the given (YYYY-MM-DD) or today's date. Read list_contacts_in_group Contacts within a group (resolved by name or resourceName). Read list_cron_jobs All active (and optionally paused) cron jobs for this user. Read list_directory List files + subdirectories. Hides denied entries (e.g. .ssh, .config). Read list_drafts Pending drafts (id + subject + to). Read list_events Events in [start, end] (ISO-8601). Default calendar = primary. Read list_gmail_accounts list_gmail_accounts Read list_groups All contact groups (Google labels: family, work, custom, etc.). Read list_memories Browse stored memories, optionally filtered by tag. Excludes expired. Read list_projects All project names currently used as task.source for this user. Read list_reminders List reminders. active_only filters out fired/cancelled. time_range = [start_iso, end_iso] on next_fire_at. Read list_tasks List tasks. filter keys: status ('pending'|'done'), project (str), min_priority (int), due_before (ISO). Read list_templates List PDF templates available in NEXUS_PDF_TEMPLATES_DIR. Read list_unread Recent unread messages. folder is a Gmail label name (INBOX, IMPORTANT, etc.). Read lookup_decision Find decisions whose topic contains the query (case-insensitive). Read memory_stats Counts: total memories, total decisions, total journal entries, top tags. Read monitor_url_for_changes monitor_url_for_changes Read omer_count Count of the Omer for the given date if applicable (returns None outside Omer window). Read overdue_items All overdue active reminders + pending tasks. Read parse_email_for_action_items Return the email body + key headers so the calling LLM can extract action items. Read pause_cron_job Temporarily stop a cron job firing. Resume with resume_cron_job. Read pdf_summary Return PDF metadata + first-page text preview + page count. Read pdf_to_images Render each PDF page as PNG via pypdfium2. Caps at 50 pages per call. Read pdf_to_text Extract all text from a PDF. If output_path given, also save to .txt. Read pdf_word_count Word + character + page count for a PDF. Read random_pick Pick one item uniformly at random from a list. Read read_docx Extract text from a Word (.docx) document. Read read_email Full message content + headers + attachment list (no bytes). Read read_image_metadata Return image size, format, mode, and EXIF (if any). No image bytes. Read read_pdf Extract text content from a PDF file via pdfplumber. Read read_spreadsheet Read .xlsx or .csv. Returns header + rows (up to max_rows, hard cap 10_000). Read read_text_file Read a UTF-8 text file. Reuses Phase 4 security boundary. Returns contents + metadata. Read recall Substring search across keys + values. Tag matches also returned. Excludes expired entries. Read recall_by_key Exact key lookup. Returns the stored value or not_found. Read recall_by_tag All memories tagged with the given tag (case-insensitive). Read recent_files Files modified within the last N days. Optionally filter by extension (e.g. '.pdf'). Read recent_interactions Recent calendar events + Gmail messages involving this contact's email addresses. Read regex_test Test whether a regex pattern matches text. Returns match groups if any. Read roll_dice Roll N dice with S sides each. Read scrape_structured_data Extract fields per a CSS-selector schema. Read search_email Gmail-style query (from:, subject:, has:attachment). Optional folder + ISO date_range. Read search_flights Search Google Flights across a date range and return cheapest and fastest options. Read search_web Web search via DuckDuckGo HTML endpoint. Returns title + url + snippet per hit. Read shabbos_times Shabbat candle-lighting + havdalah for the given location and date (defaults to today). Read split_pdf Split a PDF into segments. ranges = ['1-3','5','8-10']. One file per range, named <stem>__<i>.pdf in output_di Read summarize_inbox Recent message summaries (subject/sender/snippet) from the last N hours. The CALLER (LLM) summarizes. Read today_schedule All events for today (UTC day). Read translate Translate text. NOTE: no translation provider currently configured. Read upcoming_birthdays Upcoming birthdays from Google Contacts birthday field. Requires People API integration. Read url_decode Decode a percent-encoded string. Read url_encode Percent-encode a string for use in URLs. Read uuid Generate a random UUIDv4. Read view_image Return base64-encoded image bytes for Claude vision. Max 5 MB. Read weather Current + multi-day forecast from Open-Meteo. days_ahead 0=today only (clamped 0-7). Read week_schedule All events for the next 7 days. Read weekly_review Last 7 days completed + next 7 days incoming. Read whats_next Return the next upcoming event within N hours.

EXPLORE

Related servers

Other MCP servers with similar tools — same risk classification, starter policies for each.

FAQ

Questions about Nexus Core

Can an AI agent delete data through the Nexus Core MCP server? +

Yes. The Nexus Core server exposes 8 destructive tools including cancel_event, delete, delete_contact. These permanently remove resources with no undo. PolicyLayer blocks destructive tools by default so they never reach the upstream server.

How do I prevent bulk modifications through Nexus Core? +

The Nexus Core server has 42 write tools including accept_invite, add_label, add_signature_to_pdf. Set a rate limit in your policy -- for example, 10 calls per hour prevents an agent from making more than 10 modifications per hour. PolicyLayer enforces this at the gateway, before calls reach Nexus Core.

How many tools does the Nexus Core MCP server expose? +

134 tools across 4 categories: Destructive, Execute, Read, Write. 80 are read-only. 54 can modify, create, or delete data.

How do I enforce a policy on Nexus Core? +

Register the Nexus Core MCP server in PolicyLayer, apply the suggested rules above (adjust the limits to your use case), and point your AI client at the PolicyLayer proxy URL instead of the server directly. Your agents keep the same tools; PolicyLayer evaluates every call against policy before it executes. Nothing to install, live in minutes.

Enforce policy on every Nexus Core tool call.

Deterministic rules across all 134 Nexus Core tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.

ENFORCE POLICY ON NEXUS CORE →

Instant setup, no code required.

134 Nexus Core tools catalogued and risk-classified — across an index of 43,000+ MCP servers.