# mount URL: /chirp/api/app/mount/ Section: app -------------------------------------------------------------------------------- mount - Chirp window.BENGAL_THEME_DEFAULTS = { appearance: 'light', palette: 'charcoal-bengal' }; window.Bengal = window.Bengal || {}; window.Bengal.enhanceBaseUrl = '/chirp/assets/js/enhancements'; window.Bengal.watchDom = true; window.Bengal.debug = false; window.Bengal.enhanceUrls = { 'toc': '/chirp/assets/js/enhancements/toc.736b857e.js', 'docs-nav': '/chirp/assets/js/enhancements/docs-nav.57e4b129.js', 'tabs': '/chirp/assets/js/enhancements/tabs.aac9e817.js', 'lightbox': '/chirp/assets/js/enhancements/lightbox.1ca22aa1.js', 'interactive': '/chirp/assets/js/enhancements/interactive.96c8880c.js', 'mobile-nav': '/chirp/assets/js/enhancements/mobile-nav.d991657f.js', 'action-bar': '/chirp/assets/js/enhancements/action-bar.d62417f4.js', 'copy-link': '/chirp/assets/js/enhancements/copy-link.7d9a5c29.js', 'data-table': '/chirp/assets/js/enhancements/data-table.1f5bc1eb.js', 'lazy-loaders': '/chirp/assets/js/enhancements/lazy-loaders.a5c38245.js', 'holo': '/chirp/assets/js/enhancements/holo.ee13c841.js', 'link-previews': '/chirp/assets/js/enhancements/link-previews.96620bcf.js' }; (function () { try { var defaults = window.BENGAL_THEME_DEFAULTS || { appearance: 'system', palette: '' }; var defaultAppearance = defaults.appearance; if (defaultAppearance === 'system') { defaultAppearance = (window.matchMedia && window.matchMedia('(prefers-color-scheme: dark)').matches) ? 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(storedTheme === 'system' ? defaultAppearance : storedTheme) : defaultAppearance; var palette = storedPalette ?? defaults.palette; document.documentElement.setAttribute('data-theme', theme); if (palette) { document.documentElement.setAttribute('data-palette', palette); } } catch (e) { document.documentElement.setAttribute('data-theme', 'light'); } })(); Skip to main content For a complete page index, fetch /chirp/llms.txt. ⌁⌁ DocumentationInfoAboutGet StartedBuild AppsQuality and OperationsFile TextReferenceCubeExamplesApplied TutorialsReleasesDevGitHubChirp API ReferenceForum Magnifying Glass Search ⌘K Palette Appearance Chevron Down Mode Monitor System Sun Light Moon Dark Palette Snow Lynx Brown Bengal Silver Bengal Charcoal Bengal Blue Bengal List Chirp API Reference Caret Right Internal asgi invoke invoke_plan kwargs_resolve multimap types Caret Right Ai _providers _structured errors llm streaming Caret Right App compiler diagnostics lifecycle mount registry runtime server state url_for Caret Right Cache Caret Right Backends memory null redis deferred key middleware protocol Caret Right Cli Caret Right Templates minimal scaffold shell sse v2 _check _freeze _makemigrations _new _resolve _routes _run _security_check _templates Caret Right Contracts checker declarations patterns routes rules_accessibility rules_alpine_cdn rules_boundary rules_chirpui_runtime rules_commands rules_composition rules_context_cascade rules_csrf_forms rules_debug_wiring rules_defer_falsy rules_form_routes rules_forms rules_fragment_scope rules_fragment_targets rules_htmx rules_inline rules_islands rules_kida_analysis rules_layout rules_live_blocks rules_mount_app rules_oob_registry rules_oob_targets rules_page_handlers rules_page_shell rules_reactive rules_route_contract rules_route_names rules_safety rules_sse rules_swap rules_unreachable_blocks rules_vary template_scan types utils Caret Right Data Caret Right Drivers postgres sqlite Caret Right Schema diff generate introspect operations parse types _mapping _sqlite database errors migrate pagination query types Caret Right Docs autodoc checks collection frontmatter models plugin search tools Caret Right Ext chirp_ui Caret Right Http cookies forms headers query request response sync_request Caret Right I18N catalog detection formatting middleware Caret Right Markdown errors filters renderer Caret Right Middleware _redis_rate_limit allowed_hosts auth auth_rate_limit builtin csp_nonce csrf debug_fragment_validator inject layout_debug protocol security_headers sessions static streaming_html Caret Right Pages actions context debug discovery Caret Right index bus events stream renderer resolve sections shell_actions shell_context types Caret Right Realtime events sse Caret Right Routing params route router Caret Right Security audit decorators lockout passwords urls Caret Right Server Caret Right Debug editor frames render_plan_snapshot renderers request_context styles template_context alpine debug_page debug_runtime delegation dev dev_browser_reload devtools errors fragment_dispatch fragment_targets_debug handler handler_kwargs htmx_debug htmx_safe_target islands negotiation negotiation_oob production route_explorer sender speculation_rules sse_lifecycle sync_handler terminal_checks terminal_errors view_transitions Caret Right Templating adapter composition filters fragment_target_registry integration kida_adapter macros navigation_swap oob_registry render_plan returns streaming suspense trace Caret Right Testing assertions client route_smoke sse Caret Right Tools events handler registry schema Caret Right Validation result rules chirp config context domains errors extraction freeze health live_blocks logging plugin resilience shell_actions shell_regions sources Chirp API ReferenceApp ᗢ Caret Down Link Copy URL External Open LLM text Copy Copy LLM text Share with AI Ask Claude Ask ChatGPT Ask Gemini Ask Copilot Module app.mount mount_app adapter — hoist a pre-freeze sub-app into a parent app. Design notes live in docs/rfcs/005-mount-app.md. Summary: Sub-app's pending_routes are path-prefixed and appended to the parent. Middleware, hooks, loaders, tools, and contract checks are appended — parent's entries run first, sub-app's follow. Template globals, filters, error handlers, providers, severity overrides, and freeze-param providers use parent-wins merge; dropped sub-app entries are recorded as MountAppSkips (surfaced later as INFO contract issues in category mount_app_merge). Sub-app is marked consumed — subsequent sub_app.freeze()/run() raise RuntimeError so the caller doesn't accidentally serve a half-mounted standalone runtime. Deeper page-shell registries (sections, OOB, fragment targets, layout presets, live blocks, page-discovery state) are not yet supported: mount_app raises ConfigurationError if the sub-app has populated any of them. RFC 005 §3.3 treats these as "deep contracts" whose silent override would break shell rendering; a future version may add explicit collision handling. 4Functions Functions normalize_prefix 1 str ▼ Return ``"/" + prefix.strip("/")``. Raises ``ConfigurationError`` if the resul… def normalize_prefix(prefix: str) -> str Return "/" + prefix.strip("/"). Raises ConfigurationError if the result would be "/" — mounting at root has no effect vs. registering the routes directly on the parent. Parameters Name Type Description prefix str Returns str prefixed_path 2 str ▼ Return the sub-app route's path after applying the mount prefix. ``prefix`` is… def prefixed_path(path: str, prefix: str) -> str Return the sub-app route's path after applying the mount prefix. prefix is pre-normalized to "/<something>" (see normalize_prefix()); path is whatever the sub-app registered (expected to start with "/"). Parameters Name Type Description path str prefix str Returns str _check_sub_app_simple 1 None ▼ Refuse sub-apps that carry state mount_app v1 can't hoist safely. def _check_sub_app_simple(sub_state: MutableAppState) -> None Parameters Name Type Description sub_state MutableAppState hoist 3 None ▼ Merge ``sub_state`` into ``parent_state`` at ``prefix``. Does not validate tha… def hoist(parent_state: MutableAppState, sub_state: MutableAppState, prefix: str) -> None Merge sub_state into parent_state at prefix. Does not validate that either state is mutable / pre-freeze — the caller (App.mount_app) owns the lifecycle checks. Parameters Name Type Description parent_state MutableAppState sub_state MutableAppState prefix str ← Previous lifecycle Next → registry List Magnifying Glass ESC Recent Clear Magnifying Glass No results for "" Start typing to search... ↑↓ Navigate ↵ Open ESC Close Powered by Lunr ⌁⌁ Magnifying Glass Search X Close Documentation Caret Down Info About Get Started Build Apps Quality and Operations File Text Reference Cube Examples Applied Tutorials Releases Dev Caret Down GitHub Chirp API Reference Forum Palette Appearance Chevron Down Mode Monitor System Sun Light Moon Dark Palette Snow Lynx Brown Bengal Silver Bengal Charcoal Bengal Blue Bengal © 2026 Chirp built in ᓚᘏᗢ { "linkPreviews": { "enabled": true, "hoverDelay": 200, "hideDelay": 150, "showSection": true, "showReadingTime": true, "showWordCount": true, "showDate": true, "showTags": true, "maxTags": 3, "includeSelectors": [".prose"], "excludeSelectors": ["nav", ".toc", ".breadcrumb", ".pagination", ".card", "[class*='-card']", ".tab-nav", "[class*='-widget']", ".child-items", ".content-tiles"], "allowedHosts": [], "allowedSchemes": ["https"], "hostFailureThreshold": 3, "showDeadLinks": true } } window.BENGAL_LAZY_ASSETS = { tabulator: '/chirp/assets/js/tabulator.min.js', dataTable: '/chirp/assets/js/data-table.js', mermaidToolbar: '/chirp/assets/js/mermaid-toolbar.9de5abba.js', mermaidTheme: '/chirp/assets/js/mermaid-theme.344822c5.js', graphMinimap: '/chirp/assets/js/graph-minimap.ff04e939.js', graphContextual: '/chirp/assets/js/graph-contextual.355458ba.js' }; window.BENGAL_ICONS = { close: '/chirp/assets/icons/close.911d4fe1.svg', enlarge: '/chirp/assets/icons/enlarge.652035e5.svg', copy: '/chirp/assets/icons/copy.3d56e945.svg', 'download-svg': '/chirp/assets/icons/download.04f07e1b.svg', 'download-png': '/chirp/assets/icons/image.c34dfd40.svg', 'zoom-in': '/chirp/assets/icons/zoom-in.237b4a83.svg', 'zoom-out': '/chirp/assets/icons/zoom-out.38857c77.svg', reset: '/chirp/assets/icons/reset.d26dba29.svg' }; { "prerender": [ { "where": { "and": [ { "href_matches": "/docs/*" }, { "not": { "selector_matches": "[data-external], [target=_blank], .external" } } ] }, "eagerness": "conservative" } ], "prefetch": [ { "where": { "and": [ { "href_matches": "/*" }, { "not": { "selector_matches": "[data-external], [target=_blank], .external" } } ] }, "eagerness": "conservative" } ] } Arrow Up -------------------------------------------------------------------------------- Metadata: - Word Count: 1097 - Reading Time: 5 minutes