LiteLLM / LiteLLM

LiteLLM Fireworks AI Tool Schema Rejection default null drop_params Error

Fix LiteLLM Fireworks AI tool call failures when JSON Schema contains default null in nested properties Includes evidence for LiteLLM troubleshooting demand.

Source-backed Last updated May 13, 2026 1 source Needs local verification

Category: LiteLLM
Error signature: Fireworks AI rejects tool schemas with "default": null — drop_params doesn't sanitize nested schemas
Quick fix: Compare the failing environment with a known working setup, then change one configuration value at a time.
Updated: May 13, 2026
Verification status: Source-backed
Evidence: 1 public source URL

Before you change production

This page includes public source URLs in the imported troubleshooting record. Compare those references with your version and environment before applying changes.

Reproduce the smallest failing action and save non-secret logs before changing configuration.
Check versions for LiteLLM, related SDKs, package managers, CI runners, and hosting providers.
Change one setting or dependency at a time, then rerun the same failing command or request.
Avoid destructive commands, credential rotation, billing changes, or security relaxations without a rollback plan.

What this error means

Fireworks AI rejects tool schemas with "default": null — drop_params doesn't sanitize nested schemas is a LiteLLM failure pattern reported for developers trying to fix litellm fireworks ai tool call failures when json schema contains default null in nested properties. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

When using Claude Code with Kimi K2P6 via Fireworks AI, tool calls fail because Fireworks rejects JSON Schema properties containing 'default: null' and 'title' fields inside tool parameter definitions. drop_params: true is set but has no effect on nested fields. Issue is very recent (opened 2026-05-13).

Common causes

LiteLLM proxy users routing to Fireworks AI encounter tool call failures when JSON Schema properties contain 'default: null' and 'title' fields. The drop_params setting only strips top-level unsupported parameters but fails to sanitize nested fields within tool JSON Schema, breaking AI coding tool integrations that use Claude Code.
When using Claude Code with Kimi K2P6 via Fireworks AI, tool calls fail because Fireworks rejects JSON Schema properties containing 'default: null' and 'title' fields inside tool parameter definitions. drop_params: true is set but has no effect on nested fields. Issue is very recent (opened 2026-05-13).

Quick fixes

Confirm the exact error signature matches Fireworks AI rejects tool schemas with "default": null — drop_params doesn't sanitize nested schemas.
Check the LiteLLM account, local tool state, and provider configuration involved in the failing workflow.
Compare the failing environment with a known working setup, then change one configuration value at a time.

Platform/tool-specific checks

Verify the command, editor, extension, or API client that produced the error.
Compare local settings with CI, deployment, or editor-level settings when the error appears in only one environment.
Avoid deleting credentials, local model data, or project settings until the failing scope is clear.

Step-by-step troubleshooting

Capture the exact error message and the command, editor action, or request that triggered it.
Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
Review the source evidence below and compare it with your environment.
Apply one change at a time and rerun the smallest failing action.
Keep the working fix documented for the team or deployment environment.

How to prevent it

Keep provider/tool configuration documented.
Record non-secret diagnostics such as tool version, provider name, model name, and command path.
Add a lightweight check before CI or production workflows depend on the tool.

Diagnostic flow for this page

Match Fireworks AI rejects tool schemas with "default": null — drop_params doesn't sanitize nested schemas exactly before applying the quick fix.
Compare the failing environment with LiteLLM versions, account scope, provider settings, and deployment context.
Check the listed common causes in order, starting with the cause that best matches your logs.
Use the evidence status below to decide whether to confirm against public sources or official documentation.
Apply one reversible change, rerun the smallest failing action, and keep rollback notes.

FAQ

What does Fireworks AI rejects tool schemas with "default": null — drop_params doesn't sanitize nested schemas mean in LiteLLM?

Fireworks AI rejects tool schemas with "default": null — drop_params doesn't sanitize nested schemas indicates the workflow described by "LiteLLM Fireworks AI Tool Schema Rejection default null drop_params Error" failed in a LiteLLM context. Start by confirming the exact signature and the component that emitted it.

What should I check first for Fireworks AI rejects tool schemas with "default": null — drop_params doesn't sanitize nested schemas?

Check whether this cause matches your environment: LiteLLM proxy users routing to Fireworks AI encounter tool call failures when JSON Schema properties contain 'default: null' and 'title' fields. The drop_params setting only strips top-level unsupported parameters but fails to sanitize nested fields within tool JSON Schema, breaking AI coding tool integrations that use Claude Code.

Is the Fireworks AI rejects tool schemas with "default": null — drop_params doesn't sanitize nested schemas guidance source-backed?

The "LiteLLM Fireworks AI Tool Schema Rejection default null drop_params Error" page is labeled source-backed. It has 1 public source URL from github.com, so use that evidence status when deciding how much additional verification you need.

When should I avoid the quick fix for Fireworks AI rejects tool schemas with "default": null — drop_params doesn't sanitize nested schemas?

For "LiteLLM Fireworks AI Tool Schema Rejection default null drop_params Error", avoid applying "Compare the failing environment with a known working setup, then change one configuration value at a time." when the error text differs, the affected version or provider is different, or the change would touch credentials, billing, DNS, production deploy settings, or irreversible data.

What should I collect before debugging Fireworks AI rejects tool schemas with "default": null — drop_params doesn't sanitize nested schemas?

For "LiteLLM Fireworks AI Tool Schema Rejection default null drop_params Error", collect the failing LiteLLM command or request, non-secret configuration, versions, timestamps, request IDs when available, and the smallest reproduction that still triggers the signature.