MiniMax-M2.7 / M3: tool output not propagated between chained tool calls (design_workflow → validate_design)

[sxtay1914]

Capability area: Agent harness / Tool use

What does M2.7 fail to do for you?
MiniMax-M2.7 fails to produce a valid JSON schema conforming to the validate_design tool definition when chaining from design_workflow.

What would "good" look like in M3?
validate_design receives a valid JSON schema that conforms to the tool's parameter definition — populated from the actual design_workflow result, not reconstructed from model reasoning.

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Summary

MiniMax-M2.7 and MiniMax-M3 both fail to propagate tool output across a sequential tool call chain. When design_workflow returns a schema object, both models call the next tool (validate_design) with a schema that does not match the returned output — either reconstructed, incomplete, or structurally invalid against the tool definition.

MiniMax-M2.5 does not reproduce this behavior.

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Environment

Field	Value
Models affected	MiniMax-M2.7, MiniMax-M3
Model passing	MiniMax-M2.5
Endpoint	OpenRouter
Tool calling	Sequential 2-step chain
Observed	2026-06-17 (UTC+8)

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Expected behavior

1. design_workflow is called and returns a schema object
2. The model reads the tool result
3. validate_design is called with schema set to the exact object returned in step 1, conforming to the tool's JSON schema definition

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Actual behavior

The model calls validate_design with a schema argument that does not match the design_workflow output. The model appears to reconstruct the schema from internal reasoning rather than reading the tool result, producing a value that violates the tool's parameter schema — missing required fields or structurally incorrect.

Benchmark eval output:

issues: ["Validated design is missing fields: project name, client, start date, deadline, owner, budget"]

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Tool call sequence observed

1. design_workflow(...)
   → returns: { name, information: [{name, type, ai_hint}, ...], states: [...], ... }

2. validate_design({ schema: <does not match step 1 output, fails tool schema validation> })
   → missing required information fields

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Steps to reproduce

We have an open-source MCP tool benchmark that reproduces this consistently:

Repo: https://github.com/Inistate/harness-test-bench

1. Clone the repo and follow the setup instructions
2. Run the smoke_all_tools_2 scenario against minimax/MiniMax-M2.7 or minimax/MiniMax-M3
3. Inspect Task 2 (task_2_module_design) — validate_design will be called with a schema that does not conform to the tool's parameter definition
4. Compare against a passing model (e.g. minimax/MiniMax-M2.5) running the same scenario

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Questions

1. Is this a known regression from M2.5?
2. Does the model read tool results back into context between sequential calls, or is this not guaranteed?
3. Is there a recommended pattern to ensure tool output is forwarded as-is rather than reconstructed?

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Workaround

We currently exclude M2.7 and M3 from workflows requiring sequential tool output propagation. A fix at the model level would be preferable.

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References

Reproduced across multiple runs in an independent MCP tool benchmark. M2.5 passed consistently. M2.7 scored 3/5 and M3 scored 2/5, with the T2 chain failing on every run for both models.