fix(anthropic): complete AgentRouter streams that end before terminal frames #896
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@@ -91,6 +91,7 @@ differing backup and rewrites known legacy namespaced selected ids to bare ids. | |
| | `thinkingBudgetModels?` | `string[]` | Chat models using integer `thinking_budget`; effort maps to a budget fraction. | | ||
| | `noVisionModels?` | `string[]` | Text-only models sent through the vision sidecar; matching tolerates an Ollama `:size` tag. | | ||
| | `escapeBuiltinToolNames?` | `boolean` | Escape built-in tool names for Anthropic-compatible gateways and restore them in returned calls. | | ||
| | `anthropicEofTolerance?` | `boolean` | Let an Anthropic-compatible gateway complete a stream that ends before `message_stop`, only when visible text or a complete JSON-object tool input was received. Off by default. | | ||
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When an operator enables AGENTS.md reference: docs-site/AGENTS.md:L7-L10 Useful? React with 👍 / 👎. |
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| | `googleMode?` | `"ai-studio" \| "vertex" \| "cloud-code-assist"` | Google transport/auth mode. Default `ai-studio`. | | ||
| | `project?` | `string` | Vertex or Antigravity Cloud Code Assist project id. | | ||
| | `location?` | `string` | Vertex location; environment fallback is `GOOGLE_CLOUD_LOCATION`. | | ||
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@@ -277,14 +277,50 @@ function usableToolUseId(id: unknown): string { | |
| return typeof id === "string" && id.trim() ? id : synthesizeToolUseId(); | ||
| } | ||
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| /** | ||
| * Bound repair for a malformed tool-arguments string under the compatibility profile (#658): | ||
| * a gateway such as AgentRouter can concatenate JSON objects (`{}{"value":42}`). Find the | ||
| * last parseable JSON object by scanning suffixes from each object-open brace and prefixes | ||
| * ending at each object-close brace, bounded so hostile input cannot cost unbounded time. | ||
| */ | ||
| function lastValidJsonObject(input: string, maxCandidates: number): string | undefined { | ||
| const opens: number[] = []; | ||
| const closes: number[] = []; | ||
| for (let i = 0; i < input.length; i++) { | ||
| if (input[i] === "{") opens.push(i); | ||
| else if (input[i] === "}") closes.push(i); | ||
| } | ||
| let tried = 0; | ||
| for (let i = opens.length - 1; i >= 0 && tried < maxCandidates; i--, tried++) { | ||
| const candidate = input.slice(opens[i]); | ||
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When a tolerant non-stream response contains a large malformed tool-input string with many braces, each of up to 32 suffix candidates is a near-full copy that Useful? React with 👍 / 👎. |
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| try { | ||
| const parsed = JSON.parse(candidate) as unknown; | ||
| if (parsed && typeof parsed === "object" && !Array.isArray(parsed)) return candidate; | ||
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When the final concatenated object is itself truncated but ends with a complete nested object, scanning every opening brace accepts that nested value as the repaired tool arguments. For example, AGENTS.md reference: src/AGENTS.md:L19-L19 Useful? React with 👍 / 👎. |
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| } catch { /* keep scanning */ } | ||
| } | ||
| tried = 0; | ||
| for (let i = closes.length - 1; i >= 0 && tried < maxCandidates; i--, tried++) { | ||
| const candidate = input.slice(0, closes[i] + 1); | ||
| try { | ||
| const parsed = JSON.parse(candidate) as unknown; | ||
| if (parsed && typeof parsed === "object" && !Array.isArray(parsed)) return candidate; | ||
| } catch { /* keep scanning */ } | ||
| } | ||
| return undefined; | ||
| } | ||
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| function toolUseArguments(input: unknown, lenient = false): string { | ||
| if (typeof input === "string") { | ||
| const trimmed = input.trim(); | ||
| if (!trimmed) return "{}"; | ||
| try { | ||
| JSON.parse(trimmed); | ||
| return trimmed; | ||
| } catch { | ||
| if (lenient) { | ||
| const repaired = lastValidJsonObject(trimmed, 32); | ||
| if (repaired !== undefined) return repaired; | ||
| } | ||
| // A tool call's arguments must be a JSON object. Re-encoding an unparseable string as a | ||
| // JSON *string* is the double-encoding #765 reports: the caller then receives | ||
| // `"get weather"` where an object was required and the tool call is unusable either way. | ||
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@@ -798,6 +834,7 @@ export function createAnthropicAdapter(provider: OcxProviderConfig, cacheRetenti | |
| let pendingUsage: Record<string, number> | undefined; | ||
| let pendingStopReason: string | undefined; | ||
| let emittedDone = false; | ||
| let sawVisibleText = false; | ||
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| const emitDone = function* (): Generator<AdapterEvent> { | ||
| if (emittedDone) return; | ||
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@@ -853,6 +890,7 @@ export function createAnthropicAdapter(provider: OcxProviderConfig, cacheRetenti | |
| const delta = data.delta as Record<string, unknown> | undefined; | ||
| if (!delta) break; | ||
| if (delta.type === "text_delta" && typeof delta.text === "string") { | ||
| sawVisibleText = true; | ||
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If a tolerant gateway emits AGENTS.md reference: src/AGENTS.md:L19-L19 Useful? React with 👍 / 👎. |
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| yield { type: "text_delta", text: delta.text }; | ||
| } else if (delta.type === "thinking_delta" && typeof delta.thinking === "string") { | ||
| yield { type: "thinking_delta", thinking: delta.thinking }; | ||
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@@ -951,6 +989,26 @@ export function createAnthropicAdapter(provider: OcxProviderConfig, cacheRetenti | |
| usage: usageFromAnthropic(pendingUsage), | ||
| ...(stopReason ? { stopReason } : {}), | ||
| }; | ||
| } else if (provider.anthropicEofTolerance === true) { | ||
| // AgentRouter-style compatibility profile (#658): the upstream can close the stream | ||
| // after valid content without terminal frames. Complete only when visible text was | ||
| // received or an open tool call has complete JSON-object arguments; everything else | ||
| // (incomplete tool JSON, no usable content, transport failure) stays a truncation | ||
| // error, matching the strict default. | ||
| if (currentToolCallId) { | ||
| if (streamedToolArgumentsParse(currentToolCallJson)) { | ||
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When a tolerant tool stream ends with a syntactically valid scalar or array such as AGENTS.md reference: src/AGENTS.md:L19-L19 Useful? React with 👍 / 👎. |
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| budget.closeCall(currentToolCallId); | ||
| currentToolCallId = ""; | ||
| yield { type: "tool_call_end" }; | ||
| yield* emitDone(); | ||
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When a tolerant stream exceeds the translator budget after opening a tool call, the catch at lines 966-974 emits AGENTS.md reference: src/AGENTS.md:L19-L19 Useful? React with 👍 / 👎. |
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| } else { | ||
| yield { type: "error", message: "upstream stream ended before message_stop — possible truncation" }; | ||
| } | ||
| } else if (sawVisibleText) { | ||
| yield* emitDone(); | ||
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When a tool-only AgentRouter stream sends valid arguments and AGENTS.md reference: src/AGENTS.md:L19-L19 Useful? React with 👍 / 👎.
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When a tolerant stream emits valid text and its next SSE record is truncated or contains malformed JSON, the parse failure at lines 858-863 is only debug-dropped, so this branch treats the ensuing EOF as clean and emits AGENTS.md reference: src/AGENTS.md:L19-L19 Useful? React with 👍 / 👎. |
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| } else { | ||
| yield { type: "error", message: "upstream stream ended before message_stop — possible truncation" }; | ||
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There was a problem hiding this comment. 🗄️ Data Integrity & Integration | 🟠 Major | ⚡ Quick win Implement the documented EOF completion predicate. A valid tool call that receives
Based on PR objectives, only visible text or a complete JSON object may permit early completion. 📍 Affects 2 files
🤖 Prompt for AI Agents |
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| } | ||
| } else { | ||
| yield { type: "error", message: "upstream stream ended before message_stop — possible truncation" }; | ||
| } | ||
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@@ -980,7 +1038,7 @@ export function createAnthropicAdapter(provider: OcxProviderConfig, cacheRetenti | |
| } else if (block.type === "tool_use") { | ||
| const id = usableToolUseId(block.id); | ||
| events.push({ type: "tool_call_start", id, name: toolNames.fromWire(block.name ?? "") }); | ||
| events.push({ type: "tool_call_delta", arguments: toolUseArguments(block.input, provider.anthropicEofTolerance === true) }); | ||
| events.push({ type: "tool_call_end" }); | ||
| } | ||
| } | ||
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@@ -45,6 +45,8 @@ export interface FreeDirectoryProvider { | |
| keyOptional?: boolean; | ||
| models?: string[]; | ||
| liveModels: boolean; | ||
| /** Anthropic-compatible gateways that may close streams before terminal frames. */ | ||
| anthropicEofTolerance?: boolean; | ||
| note?: string; | ||
| googleMode?: "ai-studio" | "vertex"; | ||
| } | ||
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@@ -116,7 +118,7 @@ const CONNECTABLE: Record<string, ConnectableOverride> = { | |
| // `unverified` and drops the shared verification date rather than borrowing it. | ||
| bytez: openAi("https://api.bytez.com/models/v2/openai/v1", "https://bytez.com", { verification: "unverified", lastVerified: undefined, documentationUrl: "https://docs.bytez.com/", discovery: "static", liveModels: false, models: ["meta-llama/Llama-3.3-70B-Instruct", "mistralai/Mistral-7B-Instruct-v0.3", "Qwen/Qwen2.5-72B-Instruct"], note: "The recurring-credit classification is retained from the requested catalog, but the current reset terms could not be independently verified." }), | ||
| "nous-research": openAi("https://inference-api.nousresearch.com/v1", "https://portal.nousresearch.com", { discovery: "static", liveModels: false, models: ["Hermes-4-405B", "Hermes-4-70B"] }), | ||
| agentrouter: { baseUrl: "https://agentrouter.org", dashboardUrl: "https://agentrouter.org", adapter: "anthropic", authKind: "key", supportLevel: "experimental", verification: "primary", modelsUrl: "https://agentrouter.org/v1/models", lastVerified: LAST_VERIFIED, discovery: "live", liveModels: true, anthropicEofTolerance: true }, | ||
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For existing AgentRouter configurations that do not manually add AGENTS.md reference: src/AGENTS.md:L18-L18 Useful? React with 👍 / 👎. |
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| ai21: openAi("https://api.ai21.com/studio/v1", "https://studio.ai21.com/account/api-key", { supportLevel: "supported", verification: "official", documentationUrl: "https://docs.ai21.com/reference/models" }), | ||
| baichuan: openAi("https://api.baichuan-ai.com/v1", "https://platform.baichuan-ai.com/console/apikey", { verification: "official" }), | ||
| // Verified end-to-end 2026-07-30: /v1/models returns the OpenAI-shaped live catalog (13 models), | ||
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| @@ -0,0 +1,122 @@ | ||
| import { describe, expect, test } from "bun:test"; | ||
| import { createAnthropicAdapter as createAnthropicAdapterProduction } from "../src/adapters/anthropic"; | ||
| import { FREE_PROVIDER_DIRECTORY } from "../src/providers/free-directory"; | ||
| import type { AdapterEvent, OcxProviderConfig } from "../src/types"; | ||
| import { withTestTranslatorBudget } from "./helpers/translator-budget"; | ||
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| /** | ||
| * #658: AgentRouter's Anthropic-compatible endpoint can close the stream before | ||
| * `content_block_stop`, `message_delta`, and `message_stop`. The default adapter treats | ||
| * that EOF as a fatal truncation; with `anthropicEofTolerance` enabled it may complete | ||
| * only when visible text was received or an open tool call has complete JSON-object | ||
| * arguments. These tests pin the wire behavior; no request reaches agentrouter.org. | ||
| */ | ||
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| const createAnthropicAdapter = (...args: Parameters<typeof createAnthropicAdapterProduction>) => | ||
| withTestTranslatorBudget(createAnthropicAdapterProduction(...args)); | ||
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| function providerFor(extra: Partial<OcxProviderConfig> = {}): OcxProviderConfig { | ||
| return { | ||
| adapter: "anthropic", | ||
| baseUrl: "https://agentrouter.org", | ||
| apiKey: "test-key", | ||
| authMode: "key", | ||
| ...extra, | ||
| } as OcxProviderConfig; | ||
| } | ||
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| const strict = providerFor(); | ||
| const tolerant = providerFor({ anthropicEofTolerance: true }); | ||
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| const TRUNCATION = "upstream stream ended before message_stop — possible truncation"; | ||
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| function sseResponse(events: string[]): Response { | ||
| return new Response(events.join("\n\n"), { headers: { "content-type": "text/event-stream" } }); | ||
| } | ||
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| async function collect(provider: OcxProviderConfig, events: string[]): Promise<AdapterEvent[]> { | ||
| const out: AdapterEvent[] = []; | ||
| for await (const event of createAnthropicAdapter(provider).parseStream(sseResponse(events))) out.push(event); | ||
| return out; | ||
| } | ||
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| const textEof = [ | ||
| 'event: message_start\ndata: {"type":"message_start","message":{"usage":{"input_tokens":2}}}', | ||
| 'event: content_block_start\ndata: {"type":"content_block_start","index":0,"content_block":{"type":"text","text":""}}', | ||
| 'event: content_block_delta\ndata: {"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":"visible"}}', | ||
| ]; | ||
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| function toolEof(partialJson: string, id = "toolu_1"): string[] { | ||
| return [ | ||
| 'event: message_start\ndata: {"type":"message_start","message":{}}', | ||
| `event: content_block_start\ndata: ${JSON.stringify({ type: "content_block_start", index: 0, content_block: { type: "tool_use", id, name: "get_weather" } })}`, | ||
| `event: content_block_delta\ndata: ${JSON.stringify({ type: "content_block_delta", index: 0, delta: { type: "input_json_delta", partial_json: partialJson } })}`, | ||
| ]; | ||
| } | ||
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| describe("AgentRouter Anthropic EOF tolerance (#658)", () => { | ||
| test("text EOF completes when anthropicEofTolerance is enabled", async () => { | ||
| const events = await collect(tolerant, textEof); | ||
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| expect(events).toContainEqual({ type: "text_delta", text: "visible" }); | ||
| expect(events.at(-1)).toEqual({ type: "done", usage: { inputTokens: 2, outputTokens: 0 } }); | ||
| expect(events.some(event => event.type === "error")).toBe(false); | ||
| }); | ||
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| test("the same EOF without the capability stays a truncation error", async () => { | ||
| const events = await collect(strict, textEof); | ||
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| expect(events.at(-1)).toEqual({ type: "error", message: TRUNCATION }); | ||
| expect(events.some(event => event.type === "done")).toBe(false); | ||
| }); | ||
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| test("a complete tool call at EOF closes and completes", async () => { | ||
| const events = await collect(tolerant, toolEof('{"value":42}')); | ||
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| expect(events).toContainEqual({ type: "tool_call_start", id: "toolu_1", name: "get_weather" }); | ||
| expect(events).toContainEqual({ type: "tool_call_delta", arguments: '{"value":42}' }); | ||
| expect(events.at(-1)).toEqual({ type: "done", usage: undefined }); | ||
| expect(events.some(event => event.type === "error")).toBe(false); | ||
| }); | ||
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| test("an incomplete tool call at EOF remains a truncation error", async () => { | ||
| const events = await collect(tolerant, toolEof('{"value":')); | ||
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| expect(events.at(-1)).toEqual({ type: "error", message: TRUNCATION }); | ||
| expect(events.some(event => event.type === "done" || event.type === "tool_call_end")).toBe(false); | ||
| }); | ||
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| test("EOF before any usable content remains a truncation error", async () => { | ||
| const events = await collect(tolerant, [ | ||
| 'event: message_start\ndata: {"type":"message_start","message":{}}', | ||
| ]); | ||
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| expect(events.at(-1)).toEqual({ type: "error", message: TRUNCATION }); | ||
| }); | ||
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| test("a missing tool_use id gets a stable synthesized id on the tolerant path", async () => { | ||
| const events = await collect(tolerant, toolEof('{"value":42}', "")); | ||
| const start = events.find(event => event.type === "tool_call_start"); | ||
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| expect(start?.type).toBe("tool_call_start"); | ||
| expect((start as { id: string }).id).toMatch(/^toolu_[0-9a-f]{24}$/); | ||
| expect(events.at(-1)).toEqual({ type: "done", usage: undefined }); | ||
| }); | ||
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| test("non-stream concatenated tool input keeps the last valid object when enabled", async () => { | ||
| const payload = JSON.stringify({ | ||
| content: [{ type: "tool_use", id: "toolu_1", name: "get_weather", input: '{}{"value":42}' }], | ||
| }); | ||
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| const tolerantEvents = await createAnthropicAdapter(tolerant).parseResponse(new Response(payload)); | ||
| expect(tolerantEvents).toContainEqual({ type: "tool_call_delta", arguments: '{"value":42}' }); | ||
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| const strictEvents = await createAnthropicAdapter(strict).parseResponse(new Response(payload)); | ||
| expect(strictEvents).toContainEqual({ type: "tool_call_delta", arguments: "{}" }); | ||
| }); | ||
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| test("the AgentRouter directory row declares the EOF tolerance capability", () => { | ||
| const row = FREE_PROVIDER_DIRECTORY.find(provider => provider.id === "agentrouter"); | ||
| expect(row?.anthropicEofTolerance).toBe(true); | ||
| }); | ||
| }); |
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📐 Maintainability & Code Quality | 🟡 Minor | ⚡ Quick win
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Document Anthropic Messages streaming and EOF behavior.
docs-site/src/content/docs/reference/adapters.md:54-66omits the supported SSE lifecycle events andanthropicEofTolerancebehavior. Documentmessage_start,content_block_start,content_block_delta,content_block_stop,message_delta,message_stop, anderror. State that strict EOF handling fails on truncation, while enabled tolerance allows early completion only after visible text or complete JSON-object tool input; incomplete or contentless streams remain errors.🤖 Prompt for AI Agents
Source: Path instructions