Qiao MCP — Bridge Engineering (桥梁工程)

🌉 Qiao-MCP

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Full-lifecycle bridge structural analysis — modeling, staging, code checks
桥梁全过程结构分析 MCP 服务器 — 建模、施工阶段、规范验算

Qiao-MCP is a Model Context Protocol (MCP) server that enables AI assistants to interact with bridge structural analysis software. It provides tools for creating bridge models, applying loads, running structural analysis, and reviewing results.

Features

🔧 Tools (15 domain entry points, 153 operations)

Version 0.6.0 exposes 15 domain tools. Each takes a request with an operation selector and the matching fields; its schema includes every operation's full parameter descriptions, defaults and constraints. All 153 legacy names remain directly callable with their original arguments.

For example, send {"request":{"operation":"get_model_status"}} to inspect_bridge. See request examples and compatibility. Set QIAO_MCP_CATALOG_LAYOUT=flat to list the original 153 names instead. Version 0.5.1 used the flat catalog by default.

The 151 non-image operations retain their output schemas and MCP structured content ({status, message, ...}). Connection diagnostics also expose connection_status and connected; bridge templates return the resolved node, element and property IDs. get_model_status preserves QiaoTong's state in status. The two image-capable tools return viewable MCP image content or a text summary. At domain level, 14 entry points publish combined output schemas; view_model supports mixed image/text content. Tool failures use typed MCP errors, and read-only, destructive, and open-world operations carry MCP tool annotations. The server instructions include the full tool-group overview; use list_qtmodel_api before calling an uncovered backend method through the gateway.

Input schemas include parameter descriptions, closed-set selectors, pagination bounds and fixed-size coordinate/DOF arrays. Invalid schema inputs are rejected before a backend call. A beam end release_i / release_j flag means True = release; omitting an end keeps all six DOFs connected. Load combination components use [case_type, case_name, factor], with combine_type=3 for an envelope.

Support overrides preserve omitted coordinate/additional settings. Supplying extra_parameters enables them unless extra_enabled=False explicitly clears them; this behavior also applies to older SDKs that support these options.

0.6.0: domain tools and qtmodel 2.9.3

Version 0.6.0 combines the local 0.5.2–0.5.9 improvements since GitHub release 0.5.1. It retains all 153 operations and legacy calls behind 15 domain entry points, including the per-tool corrections listed in the changelog. See the release and upgrade notes. Section creation/deletion, stage deletion and vertical prestress checking now explain their prerequisites, selection boundaries and write behavior. add_custom_temperature accepts native [reference, height, temperature] rows (reference 1=top, 2=bottom; orientation 1=local Z, 2=local Y). Two-value rows are rejected because they omit the reference. Mutation selections reject blank, Boolean and fractional IDs; renumbering requires BOTH complete lists, or BOTH omitted to intentionally renumber the whole model.

Screenshots and plots now retrieve PNG bytes for storage on the MCP host. Partial updates require unique, complete readback; checking queries preserve typed fields. Live-load results expose envelope_type=1 (maximum) or 2 (minimum). See the changelog for solver, section-numbering, group-query and idealized support corrections.

Locked installs now use qtmodel 2.9.3. With its instance context and a desktop advertising model_instance_guard=1, mutations and commits carry the same model instance identifier, including analysis worker threads. Gateway undo_model also checks model/history revisions when model_revision_schema=1; pending or uncertain edits block that Undo. On mismatch, inspect the active model and command history before deciding whether to issue another operation. Older protocols keep existing state checks. Initialize/open and legacy raw-path file routes retain their existing contracts and cannot carry this new binding; it does not provide transaction rollback or bind separate client requests into one reviewed plan.

Choosing operations

Complete Args text is published in parameter schemas; each domain lists the operations it accepts. Select the operation matching the intended effect.

Choose absolute node edits with update_node, offsets with move_nodes, and numbering with update_node_id/renumber_nodes. For sections, calc_section_property evaluates supplied geometry, get_model_data reads stored properties, and calculate_section_property rewrites all existing sections. Tendon definitions, computed losses and coordinates have separate query tools. Automatic self-weight is controlled by stages, not by creating a case named 自重.

See the domain boundaries for which entry point covers each task.

0.5.0: queries, transversal analysis, check snapshots and international loads

This version implements B1–B4 with 20 new tools and one workflow prompt. It includes all changes since 0.3.3, including work previously labeled 0.4.0. See the release notes and upgrading from 0.3.3. New commands require a supporting QiaoTong build. Live testing confirmed basic statics and partial B1 coverage; see the known backend limitations.

get_model_edit_readiness is read-only and remains accessible when model operations are blocked. Its success status means a response was received, not that editing is safe; inspect the raw readiness object. No token is retained/reused, and no stages/results are changed.

query_model_data takes a typed request, for example:

{"request": {"kind": "nodes", "structure_group_names": ["MainGirder"], "limit": 20, "offset": 0}}

Kinds: nodes, elements, boundaries, loads, node_local_axes, section_summaries. Names are lists; IDs are positive integers/lists, not range strings. Nodes need at least one filter; near and tolerance must be paired. Qiao-MCP caps filter lists/pages at 500; section summaries allow only 100 explicit IDs and 100 items per page. The structured data field preserves native page metadata without recomputing totals or slicing again. Unsupported endpoints fail explicitly rather than downloading everything for local filtering.

get_model_data additionally supports material_summaries, material_detail, load_case_summaries, load_case_detail, load_combination_summaries, load_combination_detail, construction_stage_summaries, element_section and spans. New details use one positive integer (or one-item integer list) in ids; element_section uses position=0|1. Load-case/combination detail pagination runs on the server; other list kinds retain their existing text pagination. Summaries are not full write-back snapshots, and construction stage IDs follow stage order.

configure_live_load_system explicitly selects one of the five live-load systems; clearing old definitions defaults to off. configure_operation_stage requires all four case lists; [] disables that family. These tools commit settings without running analysis.

Transversal definitions use set_transversal_vehicle / set_transversal_lane with a complete typed request and action="add"|"update". Both may replace existing definitions. Select china_transversal first. Loads use kN and lengths use m regardless of display units. Lane nodes remain in input order and must be directly joined by beam elements; distribution_widths are meters. Use the returned data.index or get_transversal_data for references. Readback retains the native lane field load_factors; map it to distribution_widths when editing.

set_transversal_case validates the referenced vehicle/lane IDs and accepts positive reduction_factors for 1..N lanes plus greater_lane_factor for more than N. remove_transversal_data requires an explicit target; vehicle/lane deletion defaults to cascade=False. Case deletion does not accept cascade. Combination and operation-stage references must be removed explicitly first.

Base-model reinforcement uses set_section_reinforcement with a complete UI-exported snapshot, or remove_section_reinforcement with an explicit full section identifier (1, 1-I, 1-J, G7-2). Every snapshot field is required; empty arrays clear that part. Six-entry outer/inner rows and model length units differ from the legacy parametric tool. Current CSAN queries are not lossless model snapshots. The new tools require model-write permission and commit once.

set_check_stirrup_snapshot preserves the full exported definition and accepts original_id for renumbering. set_element_stirrups replaces complete shear (five entries) and torsion (three entries) assignments independently: null keeps a family, [] clears it, and stirrup ID 0 means unassigned. These are separate from the legacy current-CSAN stirrup tools.

manage_check_material sets a full exported override or resets an explicit ID to its base material. manage_check_case_definition sets/removes concrete, seismic and strengthening model definitions with native enum values. The existing run_concrete_check imports the named concrete case after these commits; it does not run seismic or strengthening checks. Preserve the complete exported material properties/parameters and stored units instead of constructing partial snapshots. Reported failed, canceled or other non-success completion states are tool errors, including on older SDKs whose waiters return them without raising.

International vehicles use set_international_vehicle with a request discriminated by standard="AASHTO"|"BS"|"EN1991". Select the matching model system first. parameters and load_items must be explicit, even for {}/[]. Both add and update replace the definition; omitted/null scalars use new-definition defaults. Update locates the original name and retains its actual ID/references. Writes commit once and return a definition read back by exact name.

The SDK does not specify the BS axle-force unit. Use verified native BS axle export/query values unchanged; do not infer their unit from another standard. get_international_live_load_data(kind="vehicles"|"cases") retains complete native fields; selection and pagination run locally over its native whole-list response. Vehicle exports may contain inactive parameters for other standards: select the documented fields for the typed tool, or use the existing gateway to replay an unchanged full native definition. No global unit conversion is applied.

create_en1991_vehicle selects a native source="standard"|"user" factory with an explicit name. Standard vehicles expose effective factory controls only; their code-generated uniform loads/lengths/spacings cannot be overridden. User vehicles retain those fields plus p/dis, load_length, num and point_load; LM71 uses four 250 kN axles when both p/dis are null. Factory writes also read back the actual vehicle ID. For example, after selecting en1991:

{"request": {"source": "standard", "name": "LM71", "load_type": "LM71"}}

set_planned_lane requires the plane, reference tandem, width, vehicle count, signed offset and direction. It uses its own endpoint, distinct from add_traffic_lane(optimize=True). There is no independent planned-lane getter; its response confirms the commit, and model export/UI inspection verifies the definition. Gateway deletion must pass lane_kind="planned" to remove_lane_line.

set_international_live_load_case checks each vehicle's exact name and expected standard before writing. Subcases select ordinary/planned lanes with optimized=False|True; EN1991 rejects duplicate lane assignments. QiaoTong checks lane existence, lane kind and influence-plane membership. Factor objects use complete native field names and values; null means server defaults, including on update. Configure live_load_cases explicitly with configure_operation_stage, then use run_analysis and get_analysis_results(case_name_mode="full") with a result identifier verified from QiaoTong. Definitions never start analysis. Vehicle/case deletion remains available through remove_international_vehicle and remove_live_load_case in the existing gateway.

0.5.0 also tracks upstream 0687ffe through the existing gateway for mass/stiffness factors, flange/effective-width definitions, statistics and structure merges. Model weight queries use fixed N, independent of display units.

📦 Resources (7 resources)

💬 Prompts (5 workflows)

For ordinary static cases, get_analysis_results keeps its automatic ST: prefix. Use case_name_mode="full" with a complete identifier verified from QiaoTong results/UI for other result families. It is passed unchanged; TV/MV combination codes are not evidence of a result endpoint's naming convention.

Architecture

qiao-mcp/
├── src/qiao_mcp/
│   ├── server.py              # MCP server entry point
│   ├── tools/                 # MCP Tools (envelope-wrapped)
│   ├── resources/             # MCP Resources
│   ├── prompts/               # MCP Prompts
│   └── providers/             # Backend adapters
│       ├── __init__.py        # BridgeProvider abstract base
│       └── qtmodel_provider.py  # QiaoTong adapter
├── tests/                     # Offline unit, integration, and API contract tests
└── reference-docs/            # Local reference material (not committed)

The Provider pattern keeps the 153 operations decoupled from any single backend. Select one with BRIDGE_PROVIDER; each provider declares its own software-specific rules, so the LLM adapts without prompt changes. Currently supports:

• QTModel (qtmodel, default) — QiaoTong (桥通) bridge analysis software (user manual)

Adding a backend means implementing BridgeProvider and registering one line — no tool-layer changes. See Backend Selection.

Quick Start

Prerequisites

• Python >= 3.11
• uv package manager
• qtmodel 2.6.3 – 2.9.x, except 2.9.0 (installed by uv sync; 2.9.3 is the current lock)
• QiaoTong software running when calling backend model, analysis, or visualization operations (see Compatibility for which versions pair with which)

The MCP server can start without QiaoTong. Use check_qiaotong_connection to distinguish a connected server from software that is not running, and get_model_status to see whether a model is open and which operations the current QiaoTong state allows.

Install & Run

# Install dependencies
uv sync

# Run the server
uv run qiao-mcp

Configure in Claude Desktop

Add to your claude_desktop_config.json:

{
  "mcpServers": {
    "qiao-mcp": {
      "command": "uv",
      "args": ["--directory", "/path/to/qiao-mcp", "run", "qiao-mcp"]
    }
  }
}

Configure in Cursor

Add to .cursor/mcp.json:

{
  "mcpServers": {
    "qiao-mcp": {
      "command": "uv",
      "args": ["--directory", "/path/to/qiao-mcp", "run", "qiao-mcp"]
    }
  }
}

Configure in Reasonix (UI)

Open Settings → MCP & Tools, then add a new MCP server:

• Name: qiao-mcp
• Transport: stdio (keep default)
• Command: uv --directory /path/to/qiao-mcp run qiao-mcp
  • Replace /path/to/qiao-mcp with your actual project path
  • Windows: use backslashes D:\path\to\qiao-mcp
  • macOS/Linux: use forward slashes /path/to/qiao-mcp
• Environment (optional): UV_PYTHON=3.11

Click Add to save.

Configure in Cherry Studio (UI)

Open 设置 → 扩展 → MCP Servers, then add a new server:

• 名称 (Name): qiao-mcp
• 描述 (Description): Optional description
• 类型 (Type): 标准输入 / 输出 (stdio)
• 命令 (Command): uv
• 包管理器 (Package Manager): Select 默认 (Default)
• 参数 (Args):

  /path/to/qiao-mcp
  run
  qiao-mcp
  

  (Each line is one argument, no --directory prefix needed)
  • Replace /path/to/qiao-mcp with your actual project path

Click 保存 to save.

Test with MCP Inspector

npx @modelcontextprotocol/inspector uv run qiao-mcp

LAN debugging proxy

For cross-machine debugging, scripts/qiaotong_lan_proxy.py forwards a LAN-facing port to the QiaoTong API on the same machine. It uses 45125 for the proxy and forwards to the selected QiaoTong process on 127.0.0.1:55125:

python scripts/qiaotong_lan_proxy.py

Then point the client machine at:

from qtmodel import mdb

mdb.set_url("http://<proxy-machine-LAN-IP>:45125/pythonForQt/")

The proxy prints each forwarded request and response. When several QiaoTong processes are running, keep one process on 55125 for this fixed proxy, or use separate proxy instances and ports for separate processes.

An SSH tunnel is an alternative that does not expose the API port on the LAN:

ssh -N -L 45125:127.0.0.1:55125 <user>@<qiaotong-machine-LAN-IP>

Use http://localhost:45125/pythonForQt/ in the client machine while the tunnel is running. Windows HTTP.sys validates the Host header and rejects 127.0.0.1 with 400 Invalid Hostname in this setup.

Development

# Install in dev mode (includes ruff, mypy, pytest)
uv sync

# Run directly
uv run python -m qiao_mcp.server

# Quality checks and offline regression tests
uv run ruff check src/ tests/
uv run mypy src/qiao_mcp/
uv run pytest tests/ --ignore=tests/test_end_to_end.py -q

The command above runs offline — it does not require the QiaoTong software. Provider/tool calls are validated against the installed qtmodel API signatures (contract tests) and dispatched against an in-process fake backend. The excluded end-to-end test requires a disposable QiaoTong model: it clears and rebuilds the active model before solving.

Backend: QTModel (桥通)

This MCP server wraps the qtmodel Python API which provides access to:

• mdb — Model database: querying, building & modifying bridge models
• odb — Output database: querying analysis results & visualization
• cdb — Check database: structural verification & code checking

Versioning

Qiao-MCP versions independently from qtmodel — the project iterates on its own (bug fixes, new tools, docs) without waiting for a backend release, and a backend release does not force a version bump here. The backend requirement is expressed where it belongs: in the dependency constraint.

Compatibility

Known lower-bound limitation: qtmodel 2.6.3 lacks get_load_group_names, so the one-shot bridge workflow tools cannot run on that version. This is an existing limitation; use 2.6.4 or later for those workflows (2.9.0 remains excluded). The dependency range does not guarantee every new tool on every build: missing methods or incompatible parameters fail explicitly before writes. The offline suite is run against PyPI 2.6.3, 2.6.4, 2.8.2, 2.9.1, 2.9.2 and 2.9.3, plus reference 0687ffe. These tests verify software contracts; complete engineering acceptance remains pending. qtmodel 2.9.3 explicitly rejects historical check-snapshot and planned-lane add/update routes with API_NOT_OPEN; a method appearing in the SDK catalog does not prove that its desktop route exists.

How the two sides are matched changed in qtmodel 2.8.2:

• qtmodel 2.6 / 2.7 perform a strict version handshake — the QiaoTong API version and the installed qtmodel must match exactly, otherwise check_qiaotong_connection reports version_mismatch and refuses to connect.
• qtmodel 2.8.2 removed that handshake. Any QiaoTong that exposes the Python API connects, so version_mismatch no longer occurs. The trade-off is that an older QiaoTong may simply lack newer commands; get_model_status surfaces that as state_unknown (the software predates the model-state handshake) so tools fail closed instead of writing blind.

Different builds report qtmodel 2.8.2: the PyPI wheel (2026-08-20) does not include QtServer.get_model_state, while the upstream source at the same version does. Qiao-MCP detects the capability rather than the version — without it the model-state guard is skipped (guard_unavailable) and tools behave as in 0.3.1; with it, every tool is gated on the state QiaoTong reports. qtmodel 2.9.0 is the first PyPI release that includes it, so on 2.9.x the guard is always active.

Live-tested backend limitations

Live testing on 2026-10-12 used QiaoTong 26.1.116.1010 with qtmodel 2.9.2. An isolated cantilever model passed reaction, bending-moment and translation checks; tip displacement differed from the shear-inclusive hand calculation by about 0.00125%. The same run confirmed these backend limitations:

• GET-DEFORMATION returns an incorrect rz, equal to ry in the tested cases. The solver database contains the correct Rz. Do not rely on the API Rz from this build; Qiao-MCP does not invent a replacement value.
• configure_live_load_system is rejected with 未知参数：clear_existing. The transversal workflow stops at system selection. International workflows share that prerequisite and were not run; individual international interfaces were not established as unsupported by this test.
• SET-SECTION-REINFORCEMENT, SET-CHECK-STIRRUP and SET-CHECK-CASE are rejected as unknown commands. Full reinforcement/check-snapshot acceptance remains open.

connected or compatible does not certify these features. Use a supporting QiaoTong build and verify these features on a disposable model. BS axle-force units also remain unconfirmed upstream.

Upgrading from 0.3.3

0.5.0 includes an incompatible correction to add_nodal_mass:

• Use mass for equal translational mass along X, Y and Z, for example {"node_id": 1, "mass": 10}. Optional mass_x/mass_y/mass_z override individual directions; omitted directions use mass, whose default is zero.
• mass_rm is removed. Specify the intended rotational inertia axis with rot_x, rot_y or rot_z; do not mechanically rename the old parameter.
• Unequal directional masses require an SDK with mass_xyz support (the supported PyPI 2.9 builds are 2.9.1 and 2.9.2). Older builds reject them before writing.

Earlier versions put some translational mass arguments into rotational fields. Upgrading the package does not repair existing models: read back previously written nodal masses and check them against the intended engineering values. Also review the changelog for stricter creep/material validation, fractional stage durations and the model-state requirements above.

Upstream qtmodel 2.9 alignment

The current reference is 0687ffe, labeled 2.9.2 but different from the PyPI 2.9.2 wheel. The earlier local baseline was 8ae651e, whose package matched that wheel apart from its older version label.

• Write safety. A write whose reply is lost raises CommandOutcomeUnknownError and is no longer resent. Qiao-MCP reports it as an unknown outcome and tells the client to read the model back before doing anything else.
• Client-side validation. Many writes now reject malformed values before sending them. Qiao-MCP's schemas match: nonempty creep/shrink curves, 26- or 29-value section property tables, per-code creep parameter counts and data_info for custom materials.
• Nodal mass layout. add_nodal_mass documents mass_info as (mass, inertia X, Y, Z) and adds mass_xyz for direction-specific masses. Qiao-MCP now sends that layout (see the changelog for the corrected fields).
• Existing tools expose new parameters. Construction stages support fractional durations and sub_steps; create_material adds is_orthotropic / ey; set_support and add_elastic_support add coordinate, extra_enabled and eight-value extra_parameters. Unidirectional elastic supports also accept signed axis_direction. add_influence_plane adds always_divided_by_beam_shape, and create_live_load_case adds the per-sub-case boolean list sub_case_optimized. Omitted options keep legacy behavior; explicit options are checked against the installed signature before writing. Fractional stage creation is rejected on builds that would truncate it. These additions are included in 0.5.0; its catalog has 153 tools.
• Operation settings and cascade deletion. configure_operation_stage exposes all four case lists, including transversal cases. The gateway method update_operation_stage_setting remains available; supply all intended case lists because omitted/empty lists disable their analysis. remove_material defaults to cascade=True (also deletes associated tendon properties and tendons). remove_tendon_property defaults to False; True deletes referencing tendons and their loads without a dialog. Confirm the deletion scope first; omitting both name and index targets all objects.
• Dedicated tools and long-tail APIs. 0.5.0 adds dedicated transversal, international/planned-lane, reinforcement/check-snapshot and edit-readiness tools. Exact object deletion (delete_model_object), factors, effective widths, statistics and structure merges remain available through the gateway. Every MDB write and the explicit CDB model-snapshot methods commit with .

Upstream Source Changes (2026-09-04–08)

These changes, first synced at 2316654 while still labeled 2.8.2, are part of 2.9.0:

• ac4dbad moves model queries from odb to mdb. Qiao-MCP prefers the new namespace and falls back to odb when the method is absent. Existing-model section geometry uses mdb.get_model_section_shape; mdb.get_section_shape remains the local geometry builder. Analysis results and views stay on odb.
• bc1ee99 returns typed model records supporting to_dict() and Mapping. The provider recursively converts them to plain JSON data for tools, resources and the API gateway, preserving original server fields. MDB query calls use read permission, not model-write permission, and never refresh the model. State-changing calls such as calculate_section_property still require model-write permission.
• 6821413 splits model objects into domain modules and keeps core.model_db as a compatibility export. The adapter does not depend on those internal paths.
• The September 7–8 updates add t_out to thickness definitions, show_view to solving, twelve analysis-setting reset APIs and three batch thickness APIs. Qiao-MCP exposes the two new options on its existing tools; the fifteen management APIs are available through the discover-then-call gateway.

Build compatibility: these options and management APIs ship in the PyPI 2.9.x releases; the PyPI 2.8.2 build (August 20) lacks them. Default tool calls keep working on either; explicit t_out or show_view=True requests fail before writing or starting a solve if the installed API does not accept them. A matching version label alone does not establish feature support.

MCP tool-call examples with a supporting qtmodel build:

add_thickness(name="Deck", t=0.20, t_out=0.30, thick_type=0)
run_analysis(read_timeout=3600, show_view=True)
list_qtmodel_api(api_object="mdb", pattern="thickness")
call_qtmodel_api(api_object="mdb", method="copy_thicknesses", kwargs={"ids": [1, 2]})
list_qtmodel_api(api_object="mdb", pattern="reset_")

thick_type means 0 = ordinary plate, 1 = ribbed plate, not equal/unequal in-plane and out-of-plane thickness. Omitting t_out uses t for both. show_view controls the QiaoTong progress window only: solving still uses background execution, polling and MCP progress heartbeats.

Batch thickness APIs accept positive integer IDs or lists, not range strings. remove_thicknesses([]) deletes nothing. Analysis resets delete settings, and arrange_thickness_ids changes IDs and references; discover the intended method and confirm the intended change before calling these write APIs.

To test the reference source without replacing the installed package (macOS/Linux):

PYTHONPATH=reference_codes/qtmodel-release/packages/qtmodel/src:src uv run pytest tests/ --ignore=tests/test_end_to_end.py -q

0.x signals the API is still free to change; it is not a statement about release quality. When moving to a new qtmodel minor line, raise the dependency bound and add a row to the table above.

License

Copyright 2026 Sorata (https://github.com/SorataYang)

Licensed under the Apache License, Version 2.0. See LICENSE. Additional attribution notices are available in NOTICE.