fix(bedrock): return no output instead of throwing when a Nova message has no content by kabishou11 · Pull Request #11812 · promptfoo/promptfoo

kabishou11 · 2026-10-16T13:34:41Z

novaOutputFromMessage in src/providers/bedrock/util.ts reads response.output?.message?.content.some(...). The optional chain stops before .some, so a Nova response whose message has no content array throws instead of producing an empty output:

novaOutputFromMessage({ output: { message: { role: 'assistant' } } });
// TypeError: Cannot read properties of undefined (reading 'some')

You don't need a malformed response to reach this. The Nova 2 handler in src/providers/bedrock/index.ts sends exactly this shape here: when content is missing or not an array, it calls novaOutputFromMessage(responseJson). The Converse parser already treats missing content as empty (outputMessage?.content || []).

The fix extends the optional chain to content?.some / content?.map, so missing content returns undefined, the same result as an empty response. Responses that have content are unchanged.

Test: should handle message without content without throwing in test/providers/bedrock/util.test.ts fails on main with the TypeError and passes with the fix. The file passes (8 tests), and Biome is clean.

…e has no content

chatgpt-codex-connector · 2026-10-16T13:34:57Z

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Review	Status	Commit	Review trigger
📝 Code Review	⚠️ Failed 2026-10-16T13:36:30.904682Z	`b7a1762`	PR opened

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codecov · 2026-10-16T13:38:36Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.33%. Comparing base (69f84c3) to head (5b7c7ca).

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #11812      +/-   ##
==========================================
- Coverage   89.33%   89.33%   -0.01%     
==========================================
  Files        1030     1030              
  Lines       93013    93013              
  Branches    32882    32882              
==========================================
- Hits        83093    83090       -3     
- Misses       9920     9923       +3

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👍 All Clear

Reviewed changes to Bedrock Nova response handling and associated tests. The PR makes message content optional and returns undefined instead of throwing when absent. Based on the diff, there are no new LLM-related security risks introduced.

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kimnamu · 2026-10-25T08:10:18Z

Thanks @kabishou11 for tracing this through the Nova 2 handler. The !content || !Array.isArray(content) branch handing the response straight to novaOutputFromMessage is easy to miss, and your test pins it down.

I ran novaOutputFromMessage as it exists in src/providers/bedrock/util.ts at main 5ed7767 and at this PR's head 6330857, against your shape and against raw InvokeModel responses from Bedrock (us-east-1). The PR removes the crash. The real Nova 1 responses give identical output on both, and the Nova 2 ones never reach the changed lines.

Input	main `5ed7767`	PR `6330857`
`{ output: { message: { role: 'assistant' } } }`	❌ `TypeError` at `util.ts:94`	✅ `undefined`
Nova Micro v1 reply (`end_turn`, one text block)	`"Hello there!"`	✅ same
Nova Lite v1 tool call (`tool_use`, text + toolUse blocks)	toolUse JSON	✅ same
Nova 2 Lite cut off by `max_new_tokens` (reasoning on and off)	`content` is still an array, so `index.ts:1471` never calls `novaOutputFromMessage`	✅ not affected

PR shape: message without content | stop=- | blocks=[]
  main: TypeError: Cannot read properties of undefined (reading 'some')
  PR  : undefined
live nova1-text | stop=end_turn | blocks=["text"]
  main: "Hello there!"
  PR  : "Hello there!"
live nova1-tool | stop=tool_use | blocks=["text","toolUse"]
  main: "{\"name\":\"get_weather\",\"toolUseId\":\"…\",\"input\":{\"city\":\"Paris\"}}"
  PR  : "{\"name\":\"get_weather\",\"toolUseId\":\"…\",\"input\":{\"city\":\"Paris\"}}"

How I checked

AmazonResponse and novaOutputFromMessage were copied verbatim from util.ts at each sha and run under Node 22 type stripping. The function uses nothing else from the module. I did not run the vitest suite.
Live calls were InvokeModel with schemaVersion: "messages-v1" on us.amazon.nova-micro-v1:0, us.amazon.nova-lite-v1:0 (one-tool toolConfig) and us.amazon.nova-2-lite-v1:0.
Nova 2 Lite returned stopReason: "max_tokens" with a one-block content array in all three tries: reasoningContent only (reasoning low, max_new_tokens 1 and 16) and a text block (no reasoningConfig, max_new_tokens 1). None of the requests I tried returned a message with no content key.

kabishou11 · 2026-10-25T09:21:43Z

Thanks for the live Bedrock check — glad the Nova 1 paths stay identical and the crash is gone.

fix(bedrock): return no output instead of throwing when a Nova messag…

b7a1762

…e has no content

kabishou11 requested review from mldangelo-oai and zcrab-oai as code owners October 16, 2026 13:34

fix(bedrock): mark Nova message content as optional in the response type

6330857

promptfoo-scanner Bot reviewed Oct 16, 2026

View reviewed changes

Merge branch 'main' into fix/bedrock-nova-missing-content

5b7c7ca

mldangelo-oai merged commit 8fd968a into promptfoo:main Nov 5, 2026
109 of 110 checks passed

promptfoobot Bot mentioned this pull request Nov 5, 2026

chore(main): release 0.126.0 #11978

Open

kabishou11 mentioned this pull request Nov 5, 2026

chore: bump upstream merge count to ~54 kabishou11/kabishou11#7

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fix(bedrock): return no output instead of throwing when a Nova message has no content - #11812

fix(bedrock): return no output instead of throwing when a Nova message has no content#11812
mldangelo-oai merged 3 commits into
promptfoo:mainfrom
kabishou11:fix/bedrock-nova-missing-content

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