[DOCS] Background side-query docs omit main-model fallback for gateways and Bedrock Mantle

Documentation Type

Incorrect/outdated documentation

Documentation Location

https://code.claude.com/docs/en/agent-view

Section/Topic

"Row summaries" and the provider-specific guidance for background side-queries / session-title generation on custom gateways and Bedrock Mantle

Current Documentation

The docs currently say:

The one-line summary in each row is generated by a Haiku-class model so the row can tell you what the session is doing, what it needs, or what it produced without opening the transcript. Each refresh is one short Haiku-class request through your normal provider, billed and handled under the same data usage terms as the session itself.

Elsewhere, the Bedrock guide already documents a fallback for background work:

Background tasks such as session title generation use the small/fast model, normally a Haiku-class model. On Bedrock, Claude Code defaults this to the primary model because Haiku may not be enabled in every account or region.

The gateway guide explains gateway auth and model discovery:

The discovery request authenticates the same way as inference requests: it sends ANTHROPIC_AUTH_TOKEN as a bearer token, or ANTHROPIC_API_KEY as the x-api-key header when no auth token is set...

But it does not explain how background side-queries or auto-naming choose a model on custom ANTHROPIC_BASE_URL setups.

What's Wrong or Missing?

A. The agent-view page reads as if row summaries always use a Haiku-class model

That is too broad for third-party routing setups. The Bedrock docs already describe a primary-model fallback when no Haiku model is available, so the agent-view wording is inaccurate as a general rule.

B. The gateway docs do not describe the same fallback behavior for custom ANTHROPIC_BASE_URL setups

After the v2.1.144 fix, users on custom gateways need to know that background side-queries and session auto-naming can fall back to the main model when no Haiku model is configured.

C. The Bedrock Mantle section does not say whether it follows the same background-model fallback rules

The Mantle docs cover endpoint selection, auth skipping, and model IDs, but they do not clarify what happens for background side-queries when a first-party ANTHROPIC_API_KEY is active or when no Haiku model is set.

Suggested Improvement

Update the agent-view row-summary section to say summaries normally use a Haiku-class model, but may fall back to the main model on third-party provider setups when no Haiku model is configured or available.

Add a short note in the llm-gateway guide and the Bedrock Mantle section linking this behavior to the relevant settings:

• ANTHROPIC_DEFAULT_HAIKU_MODEL
• ANTHROPIC_API_KEY
• ANTHROPIC_BASE_URL
• CLAUDE_CODE_USE_MANTLE

Suggested wording:

Background side-queries such as row summaries and session auto-naming normally use a Haiku-class model. On third-party routes including Bedrock, Vertex, Foundry, Bedrock Mantle, or custom ANTHROPIC_BASE_URL gateways, Claude Code can fall back to the main model when no Haiku model is configured or available.

Impact

Medium - Makes feature difficult to understand

Additional Context

Affected Pages:

| Page | Line(s) | Context |
|------|---------|---------|
| https://code.claude.com/docs/en/agent-view | 134-136 | Says row summaries are generated by a Haiku-class model through the normal provider |
| https://code.claude.com/docs/en/llm-gateway | 60-64 | Documents gateway auth/model discovery but not background-model fallback on custom ANTHROPIC_BASE_URL setups |
| https://code.claude.com/docs/en/amazon-bedrock | 254 | Documents Bedrock fallback to the primary model for background tasks when Haiku is unavailable |
| https://code.claude.com/docs/en/amazon-bedrock | 437-456 | Mantle section documents routing/auth variables but not background-model fallback behavior |
| https://code.claude.com/docs/en/model-config | 296-302 | Defines ANTHROPIC_DEFAULT_HAIKU_MODEL as the model for haiku and background functionality |

Total scope: 5 pages affected

Relevant changelog entry: v2.1.144 notes fixes for background side-queries on custom gateways and for background jobs auto-naming when no Haiku model is configured.