feat(cloudflare,vercel-edge): Add support for LangChain instrumentation

[RulaKhaled]

Adds support for LangChain manual instrumentation in @sentry/cloudflare and @sentry/vercel-edge.
To instrument LangChain operations, create a callback handler with Sentry.createLangChainCallbackHandler and pass it to your LangChain invocations.

import * as Sentry from '@sentry/cloudflare';
import { ChatAnthropic } from '@langchain/anthropic';

// Create a LangChain callback handler
const callbackHandler = Sentry.createLangChainCallbackHandler({
  recordInputs: true,   // Optional: record input prompts/messages
  recordOutputs: true   // Optional: record output responses
});

// Use with chat models
const model = new ChatAnthropic({
  model: 'claude-3-5-sonnet-20241022',
  apiKey: 'your-api-key'
});

await model.invoke('Tell me a joke', {
  callbacks: [callbackHandler]
});

The callback handler automatically creates spans for:

• Chat model invocations (gen_ai.chat)
• LLM invocations (gen_ai.pipeline)
• Chain executions (gen_ai.invoke_agent)
• Tool executions (gen_ai.execute_tool)

[github-actions]

size-limit report 📦

Path	Size	% Change	Change
@sentry/browser	24.63 kB	-	-
@sentry/browser - with treeshaking flags	23.11 kB	-	-
@sentry/browser (incl. Tracing)	40.97 kB	-	-
@sentry/browser (incl. Tracing, Profiling)	45.26 kB	-	-
@sentry/browser (incl. Tracing, Replay)	79.29 kB	-	-
@sentry/browser (incl. Tracing, Replay) - with treeshaking flags	68.97 kB	-	-
@sentry/browser (incl. Tracing, Replay with Canvas)	83.99 kB	-	-
@sentry/browser (incl. Tracing, Replay, Feedback)	96.16 kB	-	-
@sentry/browser (incl. Feedback)	41.3 kB	-	-
@sentry/browser (incl. sendFeedback)	29.29 kB	-	-
@sentry/browser (incl. FeedbackAsync)	34.22 kB	-	-
@sentry/react	26.31 kB	-	-
@sentry/react (incl. Tracing)	42.97 kB	-	-
@sentry/vue	29.11 kB	-	-
@sentry/vue (incl. Tracing)	42.75 kB	-	-
@sentry/svelte	24.64 kB	-	-
CDN Bundle	26.9 kB	-	-
CDN Bundle (incl. Tracing)	41.62 kB	-	-
CDN Bundle (incl. Tracing, Replay)	77.87 kB	-	-
CDN Bundle (incl. Tracing, Replay, Feedback)	83.35 kB	-	-
CDN Bundle - uncompressed	78.86 kB	-	-
CDN Bundle (incl. Tracing) - uncompressed	123.44 kB	-	-
CDN Bundle (incl. Tracing, Replay) - uncompressed	238.48 kB	-	-
CDN Bundle (incl. Tracing, Replay, Feedback) - uncompressed	251.24 kB	-	-
@sentry/nextjs (client)	45.11 kB	-	-
@sentry/sveltekit (client)	41.4 kB	-	-
@sentry/node-core	50.75 kB	+0.01%	+1 B 🔺
@sentry/node	156.93 kB	-	-
@sentry/node - without tracing	92.63 kB	-0.01%	-1 B 🔽
@sentry/aws-serverless	106.35 kB	-0.01%	-3 B 🔽

View base workflow run

[github-actions]

node-overhead report 🧳

Note: This is a synthetic benchmark with a minimal express app and does not necessarily reflect the real-world performance impact in an application.

Scenario	Requests/s	% of Baseline	Prev. Requests/s	Change %
GET Baseline	8,741	-	9,475	-8%
GET With Sentry	1,298	15%	1,349	-4%
GET With Sentry (error only)	5,944	68%	6,020	-1%
POST Baseline	1,172	-	1,189	-1%
POST With Sentry	501	43%	513	-2%
POST With Sentry (error only)	1,030	88%	1,072	-4%
MYSQL Baseline	3,193	-	3,320	-4%
MYSQL With Sentry	381	12%	431	-12%
MYSQL With Sentry (error only)	2,628	82%	2,688	-2%

View base workflow run

[cursor]

Bug: Type Assertion Causes Runtime Mismatch

The code passes a Record object { invocation_params: invocationParams } to the tags parameter which has type string[]. While the type assertion as unknown as string[] silences the compiler, this creates a type mismatch at runtime. The callback handler expects tags to be a string array, but receives an object instead, which could cause runtime errors or incorrect behavior in the actual LangChain callback handler implementation.

 

[cursor]

Bug: Future Compatibility Date Causes Errors

The compatibility_date is set to "2025-06-17" which is in the future relative to the current date (10/23/2025 according to the context). This appears to be a typo and should likely be "2024-06-17" or another valid past date. A future compatibility date may cause unexpected behavior or errors in Cloudflare Workers.