fix(backend): agent generator sets invalid model on PerplexityBlocks (#12391)

Fixes the agent generator setting `gpt-5.2-2025-12-11` (or `gpt-4o`) as
the model for PerplexityBlocks instead of valid Perplexity models,
causing 100% failure rate for agents using Perplexity blocks.

### Changes 🏗️

- **Fixer: block-aware model validation** — `fix_ai_model_parameter()`
now reads the block's `inputSchema` to check for `enum` constraints on
the model field. Blocks with their own model enum (PerplexityBlock,
IdeogramBlock, CodexBlock, etc.) are validated against their own allowed
values with the correct default, instead of the hardcoded generic set
(`gpt-4o`, `claude-opus-4-6`). This also fixes `edit_agent` which runs
through the same fixer pipeline.
- **PerplexityBlock: runtime fallback** — Added a `field_validator` on
the model field that gracefully falls back to `SONAR` instead of
crashing when an invalid model value is encountered at runtime. Also
overrides `validate_data` to sanitize invalid model values *before* JSON
schema validation (which runs in `Block._execute` before Pydantic
instantiation), ensuring the fallback is actually reachable during block
execution.
- **DB migration** — Fixes existing PerplexityBlock nodes with invalid
model values in both `AgentNode.constantInput` and
`AgentNodeExecutionInputOutput` (preset overrides), matching the pattern
from the Gemini migration.
- **Tests** — Fixer tests for block-specific enum validation, plus
`validate_data`-level tests ensuring invalid models are sanitized before
JSON schema validation rejects them.

Resolves [SECRT-2097](https://linear.app/autogpt/issue/SECRT-2097)

### Checklist 📋

#### For code changes:
- [x] I have clearly listed my changes in the PR description
- [x] I have made a test plan
- [x] I have tested my changes according to the test plan:
  - [x] All existing + new fixer tests pass
  - [x] PerplexityBlock block test passes
- [x] 11 perplexity_test.py tests pass (field_validator + validate_data
paths)
- [x] Verified invalid model (`gpt-5.2-2025-12-11`) falls back to
`perplexity/sonar` at runtime
  - [x] Verified valid Perplexity models are preserved by the fixer
  - [x] Migration covers both constantInput and preset overrides

autogpt_platform/backend/backend/blocks/perplexity.py

@@ -4,7 +4,7 @@ from enum import Enum
 from typing import Any, Literal
 
 import openai
-from pydantic import SecretStr
+from pydantic import SecretStr, field_validator
 
 from backend.blocks._base import (
     Block,
@@ -13,6 +13,7 @@ from backend.blocks._base import (
     BlockSchemaInput,
     BlockSchemaOutput,
 )
+from backend.data.block import BlockInput
 from backend.data.model import (
     APIKeyCredentials,
     CredentialsField,
@@ -35,6 +36,20 @@ class PerplexityModel(str, Enum):
     SONAR_DEEP_RESEARCH = "perplexity/sonar-deep-research"
 
 
+def _sanitize_perplexity_model(value: Any) -> PerplexityModel:
+    """Return a valid PerplexityModel, falling back to SONAR for invalid values."""
+    if isinstance(value, PerplexityModel):
+        return value
+    try:
+        return PerplexityModel(value)
+    except ValueError:
+        logger.warning(
+            f"Invalid PerplexityModel '{value}', "
+            f"falling back to {PerplexityModel.SONAR.value}"
+        )
+        return PerplexityModel.SONAR
+
+
 PerplexityCredentials = CredentialsMetaInput[
     Literal[ProviderName.OPEN_ROUTER], Literal["api_key"]
 ]
@@ -73,6 +88,25 @@ class PerplexityBlock(Block):
             advanced=False,
         )
         credentials: PerplexityCredentials = PerplexityCredentialsField()
+
+        @field_validator("model", mode="before")
+        @classmethod
+        def fallback_invalid_model(cls, v: Any) -> PerplexityModel:
+            """Fall back to SONAR if the model value is not a valid
+            PerplexityModel (e.g. an OpenAI model ID set by the agent
+            generator)."""
+            return _sanitize_perplexity_model(v)
+
+        @classmethod
+        def validate_data(cls, data: BlockInput) -> str | None:
+            """Sanitize the model field before JSON schema validation so that
+            invalid values are replaced with the default instead of raising a
+            BlockInputError."""
+            model_value = data.get("model")
+            if model_value is not None:
+                data["model"] = _sanitize_perplexity_model(model_value).value
+            return super().validate_data(data)
+
         system_prompt: str = SchemaField(
             title="System Prompt",
             default="",

autogpt_platform/backend/backend/blocks/test/test_perplexity.py

@@ -0,0 +1,81 @@
+"""Unit tests for PerplexityBlock model fallback behavior."""
+
+import pytest
+
+from backend.blocks.perplexity import (
+    TEST_CREDENTIALS_INPUT,
+    PerplexityBlock,
+    PerplexityModel,
+)
+
+
+def _make_input(**overrides) -> dict:
+    defaults = {
+        "prompt": "test query",
+        "credentials": TEST_CREDENTIALS_INPUT,
+    }
+    defaults.update(overrides)
+    return defaults
+
+
+class TestPerplexityModelFallback:
+    """Tests for fallback_invalid_model field_validator."""
+
+    def test_invalid_model_falls_back_to_sonar(self):
+        inp = PerplexityBlock.Input(**_make_input(model="gpt-5.2-2025-12-11"))
+        assert inp.model == PerplexityModel.SONAR
+
+    def test_another_invalid_model_falls_back_to_sonar(self):
+        inp = PerplexityBlock.Input(**_make_input(model="gpt-4o"))
+        assert inp.model == PerplexityModel.SONAR
+
+    def test_valid_model_string_is_kept(self):
+        inp = PerplexityBlock.Input(**_make_input(model="perplexity/sonar-pro"))
+        assert inp.model == PerplexityModel.SONAR_PRO
+
+    def test_valid_enum_value_is_kept(self):
+        inp = PerplexityBlock.Input(
+            **_make_input(model=PerplexityModel.SONAR_DEEP_RESEARCH)
+        )
+        assert inp.model == PerplexityModel.SONAR_DEEP_RESEARCH
+
+    def test_default_model_when_omitted(self):
+        inp = PerplexityBlock.Input(**_make_input())
+        assert inp.model == PerplexityModel.SONAR
+
+    @pytest.mark.parametrize(
+        "model_value",
+        [
+            "perplexity/sonar",
+            "perplexity/sonar-pro",
+            "perplexity/sonar-deep-research",
+        ],
+    )
+    def test_all_valid_models_accepted(self, model_value: str):
+        inp = PerplexityBlock.Input(**_make_input(model=model_value))
+        assert inp.model.value == model_value
+
+
+class TestPerplexityValidateData:
+    """Tests for validate_data which runs during block execution (before
+    Pydantic instantiation). Invalid models must be sanitized here so
+    JSON schema validation does not reject them."""
+
+    def test_invalid_model_sanitized_before_schema_validation(self):
+        data = _make_input(model="gpt-5.2-2025-12-11")
+        error = PerplexityBlock.Input.validate_data(data)
+        assert error is None
+        assert data["model"] == PerplexityModel.SONAR.value
+
+    def test_valid_model_unchanged_by_validate_data(self):
+        data = _make_input(model="perplexity/sonar-pro")
+        error = PerplexityBlock.Input.validate_data(data)
+        assert error is None
+        assert data["model"] == "perplexity/sonar-pro"
+
+    def test_missing_model_uses_default(self):
+        data = _make_input()  # no model key
+        error = PerplexityBlock.Input.validate_data(data)
+        assert error is None
+        inp = PerplexityBlock.Input(**data)
+        assert inp.model == PerplexityModel.SONAR

autogpt_platform/backend/backend/copilot/tools/agent_generator/fixer.py

@@ -829,8 +829,12 @@ class AgentFixer:
 
         For nodes whose block has category "AI", this function ensures that the
         input_default has a "model" parameter set to one of the allowed models.
-        If missing or set to an unsupported value, it is replaced with
-        default_model.
+        If missing or set to an unsupported value, it is replaced with the
+        appropriate default.
+
+        Blocks that define their own ``enum`` constraint on the ``model`` field
+        in their inputSchema (e.g. PerplexityBlock) are validated against that
+        enum instead of the generic allowed set.
 
         Args:
             agent: The agent dictionary to fix
@@ -840,7 +844,7 @@ class AgentFixer:
         Returns:
             The fixed agent dictionary
         """
-        allowed_models = {"gpt-4o", "claude-opus-4-6"}
+        generic_allowed_models = {"gpt-4o", "claude-opus-4-6"}
 
         # Create a mapping of block_id to block for quick lookup
         block_map = {block.get("id"): block for block in blocks}
@@ -868,20 +872,36 @@ class AgentFixer:
                 input_default = node.get("input_default", {})
                 current_model = input_default.get("model")
 
+                # Determine allowed models and default from the block's schema.
+                # Blocks with a block-specific enum on the model field (e.g.
+                # PerplexityBlock) use their own enum values; others use the
+                # generic set.
+                model_schema = (
+                    block.get("inputSchema", {}).get("properties", {}).get("model", {})
+                )
+                block_model_enum = model_schema.get("enum")
+
+                if block_model_enum:
+                    allowed_models = set(block_model_enum)
+                    fallback_model = model_schema.get("default", block_model_enum[0])
+                else:
+                    allowed_models = generic_allowed_models
+                    fallback_model = default_model
+
                 if current_model not in allowed_models:
                     block_name = block.get("name", "Unknown AI Block")
                     if current_model is None:
                         self.add_fix_log(
-                            f"Added model parameter '{default_model}' to AI "
+                            f"Added model parameter '{fallback_model}' to AI "
                             f"block node {node_id} ({block_name})"
                         )
                     else:
                         self.add_fix_log(
                             f"Replaced unsupported model '{current_model}' "
-                            f"with '{default_model}' on AI block node "
+                            f"with '{fallback_model}' on AI block node "
                             f"{node_id} ({block_name})"
                         )
-                    input_default["model"] = default_model
+                    input_default["model"] = fallback_model
                     node["input_default"] = input_default
                     fixed_count += 1
 

autogpt_platform/backend/backend/copilot/tools/agent_generator/fixer_test.py

@@ -475,6 +475,111 @@ class TestFixAiModelParameter:
 
         assert result["nodes"][0]["input_default"]["model"] == "claude-opus-4-6"
 
+    def test_block_specific_enum_uses_block_default(self):
+        """Blocks with their own model enum (e.g. PerplexityBlock) should use
+        the block's allowed models and default, not the generic ones."""
+        fixer = AgentFixer()
+        block_id = generate_uuid()
+        node = _make_node(
+            node_id="n1",
+            block_id=block_id,
+            input_default={"model": "gpt-5.2-2025-12-11"},
+        )
+        agent = _make_agent(nodes=[node])
+
+        blocks = [
+            {
+                "id": block_id,
+                "name": "PerplexityBlock",
+                "categories": [{"category": "AI"}],
+                "inputSchema": {
+                    "properties": {
+                        "model": {
+                            "type": "string",
+                            "enum": [
+                                "perplexity/sonar",
+                                "perplexity/sonar-pro",
+                                "perplexity/sonar-deep-research",
+                            ],
+                            "default": "perplexity/sonar",
+                        }
+                    },
+                },
+            }
+        ]
+
+        result = fixer.fix_ai_model_parameter(agent, blocks)
+
+        assert result["nodes"][0]["input_default"]["model"] == "perplexity/sonar"
+
+    def test_block_specific_enum_valid_model_unchanged(self):
+        """A valid block-specific model should not be replaced."""
+        fixer = AgentFixer()
+        block_id = generate_uuid()
+        node = _make_node(
+            node_id="n1",
+            block_id=block_id,
+            input_default={"model": "perplexity/sonar-pro"},
+        )
+        agent = _make_agent(nodes=[node])
+
+        blocks = [
+            {
+                "id": block_id,
+                "name": "PerplexityBlock",
+                "categories": [{"category": "AI"}],
+                "inputSchema": {
+                    "properties": {
+                        "model": {
+                            "type": "string",
+                            "enum": [
+                                "perplexity/sonar",
+                                "perplexity/sonar-pro",
+                                "perplexity/sonar-deep-research",
+                            ],
+                            "default": "perplexity/sonar",
+                        }
+                    },
+                },
+            }
+        ]
+
+        result = fixer.fix_ai_model_parameter(agent, blocks)
+
+        assert result["nodes"][0]["input_default"]["model"] == "perplexity/sonar-pro"
+
+    def test_block_specific_enum_missing_model_gets_block_default(self):
+        """Missing model on a block with enum should use the block's default."""
+        fixer = AgentFixer()
+        block_id = generate_uuid()
+        node = _make_node(node_id="n1", block_id=block_id, input_default={})
+        agent = _make_agent(nodes=[node])
+
+        blocks = [
+            {
+                "id": block_id,
+                "name": "PerplexityBlock",
+                "categories": [{"category": "AI"}],
+                "inputSchema": {
+                    "properties": {
+                        "model": {
+                            "type": "string",
+                            "enum": [
+                                "perplexity/sonar",
+                                "perplexity/sonar-pro",
+                                "perplexity/sonar-deep-research",
+                            ],
+                            "default": "perplexity/sonar",
+                        }
+                    },
+                },
+            }
+        ]
+
+        result = fixer.fix_ai_model_parameter(agent, blocks)
+
+        assert result["nodes"][0]["input_default"]["model"] == "perplexity/sonar"
+
 
 class TestFixAgentExecutorBlocks:
     """Tests for fix_agent_executor_blocks."""

autogpt_platform/backend/migrations/20260313120000_fix_perplexity_block_invalid_models/migration.sql

@@ -0,0 +1,40 @@
+-- Fix PerplexityBlock nodes that have invalid model values (e.g. gpt-4o,
+-- gpt-5.2-2025-12-11) set by the agent generator. Defaults them to the
+-- standard "perplexity/sonar" model.
+--
+-- PerplexityBlock ID: c8a5f2e9-8b3d-4a7e-9f6c-1d5e3c9b7a4f
+-- Valid models: perplexity/sonar, perplexity/sonar-pro, perplexity/sonar-deep-research
+
+UPDATE "AgentNode"
+SET "constantInput" = JSONB_SET(
+    "constantInput"::jsonb,
+    '{model}',
+    '"perplexity/sonar"'::jsonb
+)
+WHERE "agentBlockId" = 'c8a5f2e9-8b3d-4a7e-9f6c-1d5e3c9b7a4f'
+  AND "constantInput"::jsonb ? 'model'
+  AND "constantInput"::jsonb->>'model' NOT IN (
+      'perplexity/sonar',
+      'perplexity/sonar-pro',
+      'perplexity/sonar-deep-research'
+  );
+
+-- Update AgentPreset input overrides (stored in AgentNodeExecutionInputOutput).
+-- The table links to AgentNode through AgentNodeExecution, not directly.
+UPDATE "AgentNodeExecutionInputOutput" io
+SET "data" = JSONB_SET(
+    io."data"::jsonb,
+    '{model}',
+    '"perplexity/sonar"'::jsonb
+)
+FROM "AgentNodeExecution" exe
+JOIN "AgentNode" n ON n."id" = exe."agentNodeId"
+WHERE io."agentPresetId" IS NOT NULL
+  AND (io."referencedByInputExecId" = exe."id" OR io."referencedByOutputExecId" = exe."id")
+  AND n."agentBlockId" = 'c8a5f2e9-8b3d-4a7e-9f6c-1d5e3c9b7a4f'
+  AND io."data"::jsonb ? 'model'
+  AND io."data"::jsonb->>'model' NOT IN (
+      'perplexity/sonar',
+      'perplexity/sonar-pro',
+      'perplexity/sonar-deep-research'
+  );