MCP Tools¶

Packet Tracer MCP exposes 61 tools, grouped below by purpose. Tools that touch a running Packet Tracer require the live bridge to be connected.

Discover first

Call pt_list_devices (and pt_list_modules before installing expansion cards) so the LLM uses real model names, ports and cables from the catalog. Most NAT/ACL/module tools accept dry_run=True to preview the generated CLI/JS without touching PT.

Catalog & discovery¶

Tool	What it does
`pt_list_devices`	List all 74 device models with their exact ports + ~100 aliases.
`pt_get_device_details`	Ports/details for one model (accepts a model name or alias).
`pt_list_templates`	List the 9 topology templates and their defaults.
`pt_list_modules`	List expansion modules; optional `router_model` / `category` filter.
`pt_list_projects`	List saved projects under the exports directory.

Planning¶

Tool	What it does
`pt_plan_topology`	Generate a full `TopologyPlan` (devices, links, IPs, routing, DHCP).
`pt_estimate_plan`	Fast dry-run: device/link/subnet counts and complexity, no full plan.
`pt_validate_plan`	Validate a plan; returns typed errors and warnings.
`pt_fix_plan`	Auto-fix a plan (cables, port reassignment, model upgrades).
`pt_explain_plan`	Explain the plan's design choices in natural language.

Generation & export¶

Tool	What it does
`pt_generate_script`	Emit the PTBuilder JavaScript (`lwAddDevice`/`lwAddLink`/…).
`pt_generate_configs`	Emit IOS CLI configs for every router and switch + host settings.
`pt_export`	Write script, per-device configs and plan JSON to `projects/<name>/`.
`pt_load_project`	Load a previously saved project's plan.
`pt_full_build`	One-shot pipeline: plan → validate → generate → explain → (deploy).
`pt_deploy`	Copy the PTBuilder script to the clipboard + export files.

Live bridge¶

The bridge has two channels and picks one per command automatically: HTTP while the MCP Control Center window is open, and a file-bridge (the Script Engine reads a mailbox under %LOCALAPPDATA%) when the window is closed but PT is still open. Every tool below works over either. See Live deploy.

Tool	What it does
`pt_bridge_status`	Which channel is connected (HTTP, file-bridge, or both).
`pt_live_deploy`	Stream a plan into a running PT (devices, links, configs).
`pt_query_topology`	List devices currently in PT with ports and per-port IPs.
`pt_export_topology`	Full snapshot: positions, per-interface IPs, links, cable info.
`pt_save_project`	Save the running topology as a real `.pkt` file.
`pt_open_project`	Open a `.pkt` in PT (replaces the current topology).
`pt_send_raw`	Run arbitrary JS in PT's Script Engine (`wait_result` injects `reportResult`).

Live editing¶

Tool	What it does
`pt_add_device`	Add one device (validates name, model, no duplicates).
`pt_add_link`	Link two devices; validates ports are free; infers cable if omitted.
`pt_delete_link`	Remove the link on a given interface.
`pt_delete_device`	Delete a device (via `getLogicalWorkspace().removeDevice()`).
`pt_rename_device`	Rename a device.
`pt_move_device`	Move a device to new canvas coordinates.
`pt_set_port`	Low-level port attributes (bandwidth, duplex, description, MAC, power).
`pt_add_module`	Install one expansion module (auto power-cycle).
`pt_install_modules_batch`	Install several modules in one power-cycle (preferred for many).

NAT & ACL¶

Tool	What it does
`pt_apply_nat`	Apply NAT/PAT (`static` / `dynamic` / `pat`) on a live router.
`pt_remove_nat`	Remove a NAT/PAT configuration.
`pt_apply_acl`	Build, validate and apply a standard/extended/named ACL via CLI.
`pt_apply_acl_object`	Same, via PT's ACL object API (faster, fewer modal popups).
`pt_remove_acl`	Remove an ACL (and unbind it) via CLI.
`pt_remove_acl_object`	Remove an ACL via the object API.

Switching, security & tuning¶

Tool	What it does
`pt_apply_vlan`	VLANs, access ports, trunks + router `.1q` subinterfaces (inter-VLAN routing).
`pt_apply_stp`	Spanning-tree mode, root primary, per-VLAN priority, portfast, BPDU guard.
`pt_apply_port_security`	Port-security: max MACs, sticky/static MACs, violation action.
`pt_apply_hardening`	hostname, banner, enable secret, local users, SSH (RSA keys + vty), password-encryption.
`pt_apply_interface_tuning`	Serial clock-rate (DCE), bandwidth, per-interface OSPF/EIGRP knobs.

All accept dry_run=True to preview the generated CLI without touching PT.

Verification¶

Tool	What it does
`pt_diff`	Compare a plan vs the live topology (missing/extra devices, IP mismatches).
`pt_health_check`	Sweep the live topology: down links, cabled-without-IP, duplicate IPs.
`pt_verify_connectivity`	Run a real ping from a device's console and parse the result (reachable or not).

Live-state inspection¶

These read the device, not the plan — useful to confirm a change landed, or to understand a topology you didn't build. Verified against PT 9.0.0.0810.

Tool	What it does
`pt_audit_security`	Security posture of every IOS device, graded high/medium/low: missing `enable secret`, reversibly-stored credentials (type 7), `service password-encryption` off, no local users, no MOTD banner, config-register left at `0x2142`.
`pt_inspect_ports`	Per-port line/protocol status, MAC, IP, duplex, bandwidth, MTU, delay, CDP, DHCP-client, NAT mode and applied ACLs. Flags cabled-but-down and line-up-protocol-down.
`pt_read_vlans`	The switch's real VLAN database, separating your VLANs from PT's factory ones (1, 1002-1005).
`pt_device_power`	Power a device off/on with read-back — simulate an outage, or force a reboot so a router rereads its startup-config.

Canvas: capture & annotations¶

Turn a topology into something you can hand to a class. The agent stops describing the network and starts showing it.

Tool	What it does
`pt_screenshot`	Capture the logical canvas to an image file and return its path.
`pt_add_note`	Write a text note on the canvas — label a subnet, name a trunk.
`pt_clear_annotations`	Remove notes and drawings. Never touches devices or links.

Self-documenting topologies

Combine them: build with pt_full_build, label each subnet and link with pt_add_note, then pt_screenshot. The result is a diagram ready for a slide, produced from one prompt.

There is no drawing tool

Packet Tracer can draw lines and circles on the canvas, but not usefully from an extension: the size argument turned out to control stacking order rather than radius or thickness — three circles asking for 60, 60 and 300 all came out the same tiny size — and the colour arguments do not produce the colour requested. Rather than ship parameters that don't do what they say, annotation is limited to text notes.

The screenshot returns a path, not the image

A capture runs to tens of thousands of bytes. Returning it inline would fill the model's context with data nobody can look at, so the file is written to disk and only its path comes back. PNG is the default because it compresses a line diagram far better than JPG — measured on the same canvas, 33 KB versus 105 KB.

Backup & workspace¶

Tool	What it does
`pt_backup_config`	The device's real startup-config — the one it rereads on reboot — plus serial, config-register, boot images and uptime. `include_xml=True` adds the full device dump.
`pt_project_metadata`	The open project's saved filename, the PT version that wrote it, its description and the device/link count. Pass `description` to set it.
`pt_workspace_options`	Read or toggle workspace behaviour: auto-cabling, access to the real network, and the canvas labels that decide whether a screenshot is readable.

Turn auto-cabling off before a scripted build

With auto-cabling on, Packet Tracer picks the cable and the port for you. If you want a link on an exact interface, pt_workspace_options(auto_cabling=0) first.

Telemetry & QoS¶

Tool	What it does
`pt_apply_netflow`	Create, reconfigure or remove a NetFlow exporter on a router — collector address, UDP port, version, source interface, monitors — and read the result back.
`pt_read_qos`	Read the device's real class-maps and policy-maps, including each one's CLI form and which features a policy uses (bandwidth, priority, shaping, fair-queue).

NetFlow is configured natively; QoS can only be read

These two look symmetric but are not. pt_apply_netflow configures the exporter directly and verifies the result — no CLI involved. QoS, by contrast, can be read but not created programmatically, so class-maps and policy-maps are authored through IOS CLI (pt_send_raw → configureIosDevice) and pt_read_qos is how you confirm it landed.

Simulation¶

Packet Tracer's Simulation mode holds packets in an event list instead of moving them in real time, which is what makes a step-by-step trace possible.

Tool	What it does
`pt_simulation_mode`	Switch between Realtime and Simulation.
`pt_simulation_step`	Advance, rewind or reset the simulation (`forward` / `back` / `reset`).
`pt_read_packet_trace`	Read the event list: per frame the device, ingress/egress port, source, destination, traffic type and outcome — plus PT's own per-OSI-layer explanation of what the device decided and why.

pt_read_packet_trace answers why, not just what

The decision log is the same text Packet Tracer shows in its PDU Details pane. A failing ping stops being "no reply" and becomes a cause:

L3 :: The destination IP address is in the same subnet. The device sets the next-hop to destination.
L2 :: The next-hop IP address is not in the ARP table. The ARP process tries to
      send an ARP request for that IP address and buffers this packet.

There is no pt_send_pdu

Packet Tracer does not let an extension originate a packet the way the GUI's Add Simple PDU button does. Generate traffic the way a user would — pt_verify_connectivity runs a real ping — and then read the trace.

pt_audit_security never returns credentials

Passwords and hashes do not leave the device. The reader classifies each credential by its prefix and transmits only the algorithm label (md5, type7, scrypt, …) — enough to audit, without putting a hash into the LLM's context or the MCP client's logs.

Build flags

pt_plan_topology / pt_full_build accept vlans (router-on-a-stick VLAN count), dual_stack (IPv6: routers via CLI + hosts via SLAAC), ipv6_base, and wireless_laptops (Laptop-PT → wireless NIC + auto-associated Access Point).

Cable types for pt_add_link

Valid: straight, cross, serial, fiber, console, roll, phone, coaxial, auto, usb. Aliases: crossover→cross, rollover→roll. Omit cable_type to infer it from the device categories.