---
title: "Error Reference"
description: "Devframe surfaces warnings and errors as structured diagnostics: each with a unique code, a human-readable message, and a link to this documentation."
canonical_url: "https://devfra.me/errors"
---
# Error Reference

> Devframe surfaces warnings and errors as structured diagnostics: each with a unique code, a human-readable message, and a link to this documentation.

Devframe surfaces warnings and errors as structured diagnostics: each with a unique code, a human-readable message, and a link to this documentation.

## How error codes work

- Codes follow the pattern **`DF` + a 4-digit number**. Core `devframe` uses `DF00xx`–`DF07xx`; the hub reserves `DF8xxx`.
- Every page carries the message, cause, recommended fix, and the source file that emits it.
- **Level** is the diagnostic's severity: **error** or **warn**.
- Diagnostics are powered by [`nostics`](https://www.npmjs.com/package/nostics): structured codes with docs URLs, ANSI console output, and pluggable reporters.

## Devframe (DF)

Emitted by `devframe`: the framework-neutral host, RPC, streaming, assets, services, and JSON-render surfaces.

| Code                                      | Level | Title                                                |
| ----------------------------------------- | ----- | ---------------------------------------------------- |
| [DF0006](https://devfra.me/errors/DF0006) | error | RPC Function Not Registered                          |
| [DF0007](https://devfra.me/errors/DF0007) | error | AsyncLocalStorage Not Set                            |
| [DF0008](https://devfra.me/errors/DF0008) | error | View distDir Not Found                               |
| [DF0012](https://devfra.me/errors/DF0012) | warn  | Storage Parse Failed                                 |
| [DF0013](https://devfra.me/errors/DF0013) | error | Shared State Not Found                               |
| [DF0014](https://devfra.me/errors/DF0014) | error | Invalid Agent Field                                  |
| [DF0015](https://devfra.me/errors/DF0015) | error | Agent Tool Already Registered                        |
| [DF0016](https://devfra.me/errors/DF0016) | error | Agent Resource Already Registered                    |
| [DF0017](https://devfra.me/errors/DF0017) | error | MCP Server Start Failure                             |
| [DF0019](https://devfra.me/errors/DF0019) | error | Agent Requires JSON-Serializable RPC                 |
| [DF0020](https://devfra.me/errors/DF0020) | error | Non-JSON Value in JSON-Serializable RPC              |
| [DF0021](https://devfra.me/errors/DF0021) | error | RPC Function Already Registered                      |
| [DF0022](https://devfra.me/errors/DF0022) | error | RPC Function Not Registered (Update)                 |
| [DF0023](https://devfra.me/errors/DF0023) | error | RPC Function Not Registered (Get)                    |
| [DF0024](https://devfra.me/errors/DF0024) | error | Missing RPC Handler                                  |
| [DF0025](https://devfra.me/errors/DF0025) | error | Function Not in Dump Store                           |
| [DF0026](https://devfra.me/errors/DF0026) | error | No Dump Match                                        |
| [DF0027](https://devfra.me/errors/DF0027) | error | Invalid Dump Configuration                           |
| [DF0028](https://devfra.me/errors/DF0028) | error | Snapshot Type Mismatch                               |
| [DF0029](https://devfra.me/errors/DF0029) | warn  | Stream Buffer Overflow                               |
| [DF0030](https://devfra.me/errors/DF0030) | error | Unknown Stream ID                                    |
| [DF0031](https://devfra.me/errors/DF0031) | error | Write to Closed Stream                               |
| [DF0032](https://devfra.me/errors/DF0032) | error | Streaming Channel Already Registered                 |
| [DF0033](https://devfra.me/errors/DF0033) | warn  | Dev RPC Bridge Failed to Start                       |
| [DF0034](https://devfra.me/errors/DF0034) | error | Already-Namespaced Scoped Registration               |
| [DF0035](https://devfra.me/errors/DF0035) | error | Storage File Persist Failed                          |
| [DF0036](https://devfra.me/errors/DF0036) | error | RPC Call Rejected, Not Authorized                    |
| [DF0037](https://devfra.me/errors/DF0037) | error | Duplicate Service Provider                           |
| [DF0038](https://devfra.me/errors/DF0038) | error | Invalid JSON-Render Element Props                    |
| [DF0039](https://devfra.me/errors/DF0039) | error | Duplicate JSON-Render View                           |
| [DF0040](https://devfra.me/errors/DF0040) | error | JSON-Render View Used After Disposal                 |
| [DF0041](https://devfra.me/errors/DF0041) | error | JSON-Render Spec Is Not JSON-Serializable            |
| [DF0042](https://devfra.me/errors/DF0042) | error | Static Build Disabled By The Definition              |
| [DF0043](https://devfra.me/errors/DF0043) | error | Invalid RPC Argument                                 |
| [DF0044](https://devfra.me/errors/DF0044) | error | Invalid RPC Return Value                             |
| [DF0045](https://devfra.me/errors/DF0045) | warn  | Instance Registry Update Failed                      |
| [DF0046](https://devfra.me/errors/DF0046) | error | Connector Requires @devframes/agentic                |
| [DF0047](https://devfra.me/errors/DF0047) | warn  | Agent Tool Wire-Name Collision                       |
| [DF0048](https://devfra.me/errors/DF0048) | error | Unknown Shared-State Key                             |
| [DF0049](https://devfra.me/errors/DF0049) | error | Connector Call Requires Port and Tool                |
| [DF0050](https://devfra.me/errors/DF0050) | error | No Devframe Instance on Port                         |
| [DF0051](https://devfra.me/errors/DF0051) | error | Instance Has No MCP Endpoint                         |
| [DF0052](https://devfra.me/errors/DF0052) | error | HTTP Server Failed to Listen                         |
| [DF0054](https://devfra.me/errors/DF0054) | error | connectionMeta() Before Instance Ready               |
| [DF0055](https://devfra.me/errors/DF0055) | error | Instance Already Owns Its WebSocket Transport        |
| [DF0056](https://devfra.me/errors/DF0056) | error | Instance Advertises an External WebSocket Endpoint   |
| [DF0057](https://devfra.me/errors/DF0057) | error | WebSocket Transport Disabled                         |
| [DF0058](https://devfra.me/errors/DF0058) | error | Dev Server Disabled By The Definition                |
| [DF0059](https://devfra.me/errors/DF0059) | warn  | Remote Assets File Listing Failed                    |
| [DF0060](https://devfra.me/errors/DF0060) | error | Remote Asset Fetch Failed                            |
| [DF0061](https://devfra.me/errors/DF0061) | warn  | Installed Assets Package Major Version Mismatch      |
| [DF0062](https://devfra.me/errors/DF0062) | warn  | Installed Assets Package Version Skew                |
| [DF0063](https://devfra.me/errors/DF0063) | warn  | Remote Asset Cache Write Failed                      |
| [DF0064](https://devfra.me/errors/DF0064) | error | Remote Assets Materialization Failed                 |
| [DF0065](https://devfra.me/errors/DF0065) | error | Invalid Remote Assets Package Or Version             |
| [DF0066](https://devfra.me/errors/DF0066) | warn  | Service Already Installed                            |
| [DF0067](https://devfra.me/errors/DF0067) | error | Required Service Package Not Importable              |
| [DF0068](https://devfra.me/errors/DF0068) | error | Required Service Version Range Not Satisfied         |
| [DF0069](https://devfra.me/errors/DF0069) | warn  | Service Version Range Not Satisfied                  |
| [DF0070](https://devfra.me/errors/DF0070) | error | Invalid Service                                      |
| [DF0072](https://devfra.me/errors/DF0072) | warn  | Snapshot Names Unknown RPC Method                    |
| [DF0073](https://devfra.me/errors/DF0073) | error | JSON-Render Spec Does Not Match Its Schema           |
| [DF0074](https://devfra.me/errors/DF0074) | error | JSON-Render Schema Is Asynchronous                   |
| [DF0075](https://devfra.me/errors/DF0075) | warn  | No RPC Transport On This Runtime                     |
| [DF0076](https://devfra.me/errors/DF0076) | error | WebSocket Upgrade Unsupported On This Runtime        |
| [DF0077](https://devfra.me/errors/DF0077) | error | In-Page Channel Function Not Registered              |
| [DF0078](https://devfra.me/errors/DF0078) | warn  | Agent Surface Without @devframes/agentic             |
| [DF0079](https://devfra.me/errors/DF0079) | error | MCP Enabled Without @devframes/agentic               |
| [DF0080](https://devfra.me/errors/DF0080) | error | In-Page Channel Agent Function Not JSON-Serializable |
| [DF0081](https://devfra.me/errors/DF0081) | error | Invalid MCP Content Blocks                           |
| [DF0082](https://devfra.me/errors/DF0082) | error | Addressed Client Not Connected                       |
| [DF0084](https://devfra.me/errors/DF0084) | error | Invalid MCP Resource Template                        |
| [DF0085](https://devfra.me/errors/DF0085) | error | Repeated MCP Prompt Name                             |

## Hub: context & lifecycle (DF80xx)

Emitted by `@devframes/hub` while assembling and mounting the unified surface.

| Code                                      | Level | Title                                         |
| ----------------------------------------- | ----- | --------------------------------------------- |
| [DF8000](https://devfra.me/errors/DF8000) | error | Devframe Id Collides With a Reserved Hub Path |
| [DF8002](https://devfra.me/errors/DF8002) | error | Both devframes and context Passed to initHub  |
| [DF8003](https://devfra.me/errors/DF8003) | error | connectionMeta() Before Hub Instance Ready    |
| [DF8004](https://devfra.me/errors/DF8004) | error | Devframe Id Is Not a Mountable URL Segment    |

## Hub: docks & mounting (DF81xx)

| Code                                      | Level | Title                                                |
| ----------------------------------------- | ----- | ---------------------------------------------------- |
| [DF8100](https://devfra.me/errors/DF8100) | error | Dock Already Registered                              |
| [DF8101](https://devfra.me/errors/DF8101) | error | Cannot Change Dock Id                                |
| [DF8102](https://devfra.me/errors/DF8102) | error | Dock Not Registered                                  |
| [DF8103](https://devfra.me/errors/DF8103) | error | Dock Entry Cannot Group Itself                       |
| [DF8104](https://devfra.me/errors/DF8104) | error | Nested Dock Groups Unsupported                       |
| [DF8105](https://devfra.me/errors/DF8105) | error | Devframe Already Mounted                             |
| [DF8106](https://devfra.me/errors/DF8106) | warn  | Connection Meta Not Served                           |
| [DF8107](https://devfra.me/errors/DF8107) | warn  | Unknown Dock Activation Target                       |
| [DF8108](https://devfra.me/errors/DF8108) | error | Duplicate Renderer Module Type                       |
| [DF8109](https://devfra.me/errors/DF8109) | error | Renderer Module File Missing                         |
| [DF8110](https://devfra.me/errors/DF8110) | error | Renderer Type Is Not URL-Safe                        |
| [DF8111](https://devfra.me/errors/DF8111) | warn  | Bare-Specifier Client Script Without Host Resolution |

## Hub: terminals (DF82xx)

| Code                                      | Level | Title                                     |
| ----------------------------------------- | ----- | ----------------------------------------- |
| [DF8200](https://devfra.me/errors/DF8200) | error | Terminal Session Already Registered       |
| [DF8201](https://devfra.me/errors/DF8201) | error | Terminal Session Not Registered           |
| [DF8202](https://devfra.me/errors/DF8202) | error | Terminal Session Does Not Accept Input    |
| [DF8203](https://devfra.me/errors/DF8203) | error | Failed To Spawn PTY Session               |
| [DF8204](https://devfra.me/errors/DF8204) | error | Terminal Session Cannot Be Controlled     |
| [DF8205](https://devfra.me/errors/DF8205) | error | Terminal Session Is Not Restartable       |
| [DF8206](https://devfra.me/errors/DF8206) | error | Terminal Session Restart on Closed Stream |

## Hub: commands (DF84xx)

| Code                                      | Level | Title                          |
| ----------------------------------------- | ----- | ------------------------------ |
| [DF8400](https://devfra.me/errors/DF8400) | error | Command Already Registered     |
| [DF8401](https://devfra.me/errors/DF8401) | error | Cannot Change Command Id       |
| [DF8402](https://devfra.me/errors/DF8402) | error | Command Not Registered         |
| [DF8403](https://devfra.me/errors/DF8403) | error | Duplicate Command Id           |
| [DF8404](https://devfra.me/errors/DF8404) | error | Agent Exposure Without Handler |


## Sitemap

See the full [sitemap](https://devfra.me/sitemap.md) for all pages.