PerfLens MCP Server

Overview Schema Source Related Servers Discussions Admin

classify_hotspots

Read-onlyIdempotent

Apply candidate-only rules to a performance analysis and return a paginated classification page, enabling focused hotspot identification.

Instructions

Apply generic candidate-only rules and return a bounded classification page.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`limit`	No
`cursor`	No
`analysis_id`	Yes

Output Schema

TableJSON Schema

Name	Required	Default
`items`	Yes
`analysis_id`	Yes
`next_cursor`	No
`total_items`	Yes
`schema_version`	No	1.0
`evidence_quality`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed12 schema fields changedv0.3.2Aug 28, 2026

addedOutput schema / $defs / EvidenceQuality / properties / kernel_context_self_percent

Added value: +{
+  "anyOf": [
+    {
+      "maximum": 100,
+      "minimum": 0,
+      "type": "number"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "title": "Kernel Context Self Percent"
+}

addedOutput schema / $defs / EvidenceQuality / properties / kernel_context_self_weight

Added value: +{
+  "anyOf": [
+    {
+      "minimum": 0,
+      "type": "integer"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "title": "Kernel Context Self Weight"
+}

addedOutput schema / $defs / EvidenceQuality / properties / unknown_context_self_percent

Added value: +{
+  "anyOf": [
+    {
+      "maximum": 100,
+      "minimum": 0,
+      "type": "number"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "title": "Unknown Context Self Percent"
+}

addedOutput schema / $defs / EvidenceQuality / properties / unknown_context_self_weight

Added value: +{
+  "anyOf": [
+    {
+      "minimum": 0,
+      "type": "integer"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "title": "Unknown Context Self Weight"
+}

addedOutput schema / $defs / EvidenceQuality / properties / unresolved_kernel_self_percent

Added value: +{
+  "anyOf": [
+    {
+      "maximum": 100,
+      "minimum": 0,
+      "type": "number"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "title": "Unresolved Kernel Self Percent"
+}

addedOutput schema / $defs / EvidenceQuality / properties / unresolved_kernel_self_weight

Added value: +{
+  "anyOf": [
+    {
+      "minimum": 0,
+      "type": "integer"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "title": "Unresolved Kernel Self Weight"
+}

addedOutput schema / $defs / EvidenceQuality / properties / unresolved_unknown_context_self_percent

Added value: +{
+  "anyOf": [
+    {
+      "maximum": 100,
+      "minimum": 0,
+      "type": "number"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "title": "Unresolved Unknown Context Self Percent"
+}

addedOutput schema / $defs / EvidenceQuality / properties / unresolved_unknown_context_self_weight

Added value: +{
+  "anyOf": [
+    {
+      "minimum": 0,
+      "type": "integer"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "title": "Unresolved Unknown Context Self Weight"
+}

addedOutput schema / $defs / EvidenceQuality / properties / unresolved_user_self_percent

Added value: +{
+  "anyOf": [
+    {
+      "maximum": 100,
+      "minimum": 0,
+      "type": "number"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "title": "Unresolved User Self Percent"
+}

addedOutput schema / $defs / EvidenceQuality / properties / unresolved_user_self_weight

Added value: +{
+  "anyOf": [
+    {
+      "minimum": 0,
+      "type": "integer"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "title": "Unresolved User Self Weight"
+}

addedOutput schema / $defs / EvidenceQuality / properties / user_context_self_percent

Added value: +{
+  "anyOf": [
+    {
+      "maximum": 100,
+      "minimum": 0,
+      "type": "number"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "title": "User Context Self Percent"
+}

addedOutput schema / $defs / EvidenceQuality / properties / user_context_self_weight

Added value: +{
+  "anyOf": [
+    {
+      "minimum": 0,
+      "type": "integer"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "title": "User Context Self Weight"
+}

Changed3 schema fields changedv0.3.0Aug 21, 2026

addedOutput schema / $defs / EvidenceQuality

Added value: +{
+  "additionalProperties": false,
+  "properties": {
+    "actual_event_source": {
+      "default": "unknown",
+      "enum": [
+        "hardware",
+        "software",
+        "unknown"
+      ],
+      "title": "Actual Event Source",
+      "type": "string"
+    },
+    "address_annotation_line_count": {
+      "minimum": 0,
+      "title": "Address Annotation Line Count",
+      "type": "integer"
+    },
+    "aggregated_frame_occurrence_count": {
+      "minimum": 0,
+      "title": "Aggregated Frame Occurrence Count",
+      "type": "integer"
+    },
+    "allowed_conclusions": {
+      "default": [],
+      "items": {
+        "type": "string"
+      },
+      "title": "Allowed Conclusions",
+      "type": "array"
+    },
+    "call_graph_weight": {
+      "minimum": 0,
+      "title": "Call Graph Weight",
+      "type": "integer"
+    },
+    "call_graph_weight_percent": {
+      "maximum": 100,
+      "minimum": 0,
+      "title": "Call Graph Weight Percent",
+      "type": "number"
+    },
+    "collection_limitations": {
+      "default": [],
+      "items": {
+        "type": "string"
+      },
+      "title": "Collection Limitations",
+      "type": "array"
+    },
+    "duplicate_frame_line_count": {
+      "minimum": 0,
+      "title": "Duplicate Frame Line Count",
+      "type": "integer"
+    },
+    "event": {
+      "title": "Event",
+      "type": "string"
+    },
+    "exported_call_path_count": {
+      "minimum": 0,
+      "title": "Exported Call Path Count",
+      "type": "integer"
+    },
+    "exported_hotspot_count": {
+      "minimum": 0,
+      "title": "Exported Hotspot Count",
+      "type": "integer"
+    },
+    "fallback_reason": {
+      "anyOf": [
+        {
+          "type": "string"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null,
+      "title": "Fallback Reason"
+    },
+    "fallback_used": {
+      "anyOf": [
+        {
+          "type": "boolean"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null,
+      "title": "Fallback Used"
+    },
+    "forbidden_conclusions": {
+      "default": [],
+      "items": {
+        "type": "string"
+      },
+      "title": "Forbidden Conclusions",
+      "type": "array"
+    },
+    "frame_line_count": {
+      "minimum": 0,
+      "title": "Frame Line Count",
+      "type": "integer"
+    },
+    "inline_frame_count": {
+      "minimum": 0,
+      "title": "Inline Frame Count",
+      "type": "integer"
+    },
+    "input_bytes": {
+      "minimum": 0,
+      "title": "Input Bytes",
+      "type": "integer"
+    },
+    "input_sha256": {
+      "pattern": "^[a-f0-9]{64}$",
+      "title": "Input Sha256",
+      "type": "string"
+    },
+    "limitations": {
+      "default": [],
+      "items": {
+        "type": "string"
+      },
+      "title": "Limitations",
+      "type": "array"
+    },
+    "malformed_record_count": {
+      "minimum": 0,
+      "title": "Malformed Record Count",
+      "type": "integer"
+    },
+    "normalization_merge_count": {
+      "minimum": 0,
+      "title": "Normalization Merge Count",
+      "type": "integer"
+    },
+    "omitted_call_path_weight": {
+      "minimum": 0,
+      "title": "Omitted Call Path Weight",
+      "type": "integer"
+    },
+    "omitted_hotspot_self_weight": {
+      "minimum": 0,
+      "title": "Omitted Hotspot Self Weight",
+      "type": "integer"
+    },
+    "parser_invariants_passed": {
+      "title": "Parser Invariants Passed",
+      "type": "boolean"
+    },
+    "quality_status": {
+      "enum": [
+        "verified",
+        "partial"
+      ],
+      "title": "Quality Status",
+      "type": "string"
+    },
+    "sample_count": {
+      "minimum": 0,
+      "title": "Sample Count",
+      "type": "integer"
+    },
+    "schema_version": {
+      "const": "1.0",
+      "default": "1.0",
+      "title": "Schema Version",
+      "type": "string"
+    },
+    "source_annotation_line_count": {
+      "minimum": 0,
+      "title": "Source Annotation Line Count",
+      "type": "integer"
+    },
+    "source_collection_artifact_sha256": {
+      "anyOf": [
+        {
+          "pattern": "^[a-f0-9]{64}$",
+          "type": "string"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null,
+      "title": "Source Collection Artifact Sha256"
+    },
+    "source_collection_id": {
+      "anyOf": [
+        {
+          "type": "string"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null,
+      "title": "Source Collection Id"
+    },
+    "source_line_frame_count": {
+      "minimum": 0,
+      "title": "Source Line Frame Count",
+      "type": "integer"
+    },
+    "source_line_self_percent": {
+      "maximum": 100,
+      "minimum": 0,
+      "title": "Source Line Self Percent",
+      "type": "number"
+    },
+    "source_line_self_weight": {
+      "minimum": 0,
+      "title": "Source Line Self Weight",
+      "type": "integer"
+    },
+    "source_locations_truncated_hotspot_count": {
+      "minimum": 0,
+      "title": "Source Locations Truncated Hotspot Count",
+      "type": "integer"
+    },
+    "total_call_path_count": {
+      "minimum": 0,
+      "title": "Total Call Path Count",
+      "type": "integer"
+    },
+    "total_hotspot_count": {
+      "minimum": 0,
+      "title": "Total Hotspot Count",
+      "type": "integer"
+    },
+    "total_weight": {
+      "minimum": 0,
+      "title": "Total Weight",
+      "type": "integer"
+    },
+    "unicode_replacement_count": {
+      "minimum": 0,
+      "title": "Unicode Replacement Count",
+      "type": "integer"
+    },
+    "unresolved_self_percent": {
+      "maximum": 100,
+      "minimum": 0,
+      "title": "Unresolved Self Percent",
+      "type": "number"
+    },
+    "unresolved_self_weight": {
+      "minimum": 0,
+      "title": "Unresolved Self Weight",
+      "type": "integer"
+    },
+    "warning_count": {
+      "minimum": 0,
+      "title": "Warning Count",
+      "type": "integer"
+    },
+    "warnings_truncated": {
+      "title": "Warnings Truncated",
+      "type": "boolean"
+    },
+    "weight_source": {
+      "title": "Weight Source",
+      "type": "string"
+    },
+    "weight_unit": {
+      "title": "Weight Unit",
+      "type": "string"
+    }
+  },
+  "required": [
+    "quality_status",
+    "parser_invariants_passed",
+    "input_sha256",
+    "input_bytes",
+    "sample_count",
+    "total_weight",
+    "event",
+    "weight_unit",
+    "weight_source",
+    "malformed_record_count",
+    "warning_count",
+    "warnings_truncated",
+    "unicode_replacement_count",
+    "frame_line_count",
+    "duplicate_frame_line_count",
+    "address_annotation_line_count",
+    "source_annotation_line_count",
+    "aggregated_frame_occurrence_count",
+    "unresolved_self_weight",
+    "unresolved_self_percent",
+    "call_graph_weight",
+    "call_graph_weight_percent",
+    "source_line_frame_count",
+    "source_line_self_weight",
+    "source_line_self_percent",
+    "inline_frame_count",
+    "normalization_merge_count",
+    "source_locations_truncated_hotspot_count",
+    "total_hotspot_count",
+    "exported_hotspot_count",
+    "omitted_hotspot_self_weight",
+    "total_call_path_count",
+    "exported_call_path_count",
+    "omitted_call_path_weight"
+  ],
+  "title": "EvidenceQuality",
+  "type": "object"
+}

addedOutput schema / properties / evidence_quality

Added value: +{
+  "$ref": "#/$defs/EvidenceQuality"
+}

changedOutput schema / required

Previous value: -[
-  "analysis_id",
-  "items",
-  "total_items"
-]New value: +[
+  "analysis_id",
+  "evidence_quality",
+  "items",
+  "total_items"
+]

First observedv0.1.0Aug 1, 2026

TDQS

B3/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the description only needs to add context beyond those. It adds two useful behavioral facts: the classification is restricted to candidates ('candidate-only') and the result is a bounded page, which connects to the limit/cursor parameters. There is no contradiction with the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single front-loaded sentence with no filler. It loses a point because 'generic candidate-only' is jargon that could be clearer, but the structure is appropriately compact.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The tool is simple, and the annotations plus output schema cover safety and return shape, so the description need not repeat those. Still, the description does not clarify what 'candidate' means or how classify_hotspots relates to the many sibling hotspot/collection tools, leaving an agent to infer selection context.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters2/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must compensate for the three parameters. It only hints at pagination via 'bounded classification page' and never explains the required analysis_id, limit, or cursor semantics.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose3/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states an action ('Apply...rules') and a result ('return a bounded classification page'), so it is not a tautology. However, 'generic candidate-only rules' is vague and the description never explicitly names the resource ('hotspots') or distinguishes itself from siblings like get_hotspot_details and list_hotspots.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no guidance on when to use this tool versus alternatives. It does not mention get_hotspot_details, list_hotspots, or analyze_collection, and 'candidate-only' only weakly implies a scope without saying when an agent should prefer another sibling.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Deploy Server