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Compare two periods

compare_metric_periods

Read-onlyIdempotent

Compare a metric's average between two date ranges to assess changes, such as this month vs. last month or before vs. after a new medication.

Instructions

Compare one metric's average between two date ranges — e.g. "this month vs. last month" or "since starting a new medication vs. before." The two ranges may be any length and need not be adjacent or equal in size; each is summarized with its own baseline first.

Use this tool when:

the user names or implies two distinct date ranges to weigh against each other (e.g. "compare my average steps this month to last month", "since starting a new medication vs. before").

Do not use this tool when:

there's only one continuous window and the question is about direction over time, not two discrete ranges -> use calculate_metric_trend instead.
the user wants "what's normal" for a single window, not a before/after comparison -> use get_baseline instead.

Privacy note: this server and its SQLite file are entirely local, but the data returned by this tool becomes part of the conversation sent to whatever model the calling client is configured with. If that model runs in the cloud rather than on your machine, treat this the same as pasting the data into a chat with that provider.

Input Schema

TableJSON Schema

Name	Required	Description
`metric`	Yes	One of steps, sleep_hours, resting_heart_rate, weight_kg, workout_minutes, mood, water_ml, heart_rate, hrv_ms.
`period_a_end`	Yes
`period_b_end`	Yes
`period_a_start`	Yes
`period_b_start`	Yes

Output Schema

TableJSON Schema

Name	Required	Description
`claim`	Yes	Evidence and decision for the period comparison claim; read claim.decision before reporting it.
`delta`	No
`metric`	Yes
`period_a`	Yes
`period_b`	Yes
`pct_change`	No
`period_a_stats`	Yes
`period_b_stats`	Yes
`period_a_evidence`	Yes	DEPRECATED: identical to claim.evidence_a. Use claim.decision, not a standalone confidence field.
`period_b_evidence`	Yes	DEPRECATED: identical to claim.evidence_b. Use claim.decision, not a standalone confidence field.

Schema Changelog

Changes observed during successful MCP inspections.

Changed3 schema fields changedv1.0.28Sep 30, 2026

removedOutput schema / properties / claim_decision

Removed value: -{
-  "deprecated": true,
-  "description": "DEPRECATED: identical to claim.decision. Use claim.decision instead.",
-  "properties": {
-    "must_state": {
-      "items": {
-        "type": "string"
-      },
-      "type": "array"
-    },
-    "permitted_phrasing_class": {
-      "type": "string"
-    },
-    "template": {
-      "type": "string"
-    },
-    "tier": {
-      "type": "string"
-    }
-  },
-  "required": [
-    "tier",
-    "permitted_phrasing_class",
-    "must_state",
-    "template"
-  ],
-  "type": "object"
-}

removedOutput schema / properties / evidence_profile

Removed value: -{
-  "deprecated": true,
-  "description": "DEPRECATED: identical to claim.profile. Use claim.decision instead.",
-  "properties": {
-    "analysis": {
-      "type": "string"
-    },
-    "dimensions": {
-      "items": {
-        "properties": {
-          "can_block": {
-            "default": true,
-            "type": "boolean"
-          },
-          "details": {
-            "additionalProperties": true,
-            "type": "object"
-          },
-          "dimension": {
-            "enum": [
-              "sample",
-              "temporal",
-              "robustness",
-              "missingness",
-              "practical",
-              "measurement_validity",
-              "provenance"
-            ],
-            "type": "string"
-          },
-          "reason_codes": {
-            "items": {
-              "type": "string"
-            },
-            "type": "array"
-          },
-          "status": {
-            "enum": [
-              "adequate",
-              "negligible",
-              "not_assessed",
-              "weak",
-              "concern",
-              "blocking"
-            ],
-            "type": "string"
-          }
-        },
-        "required": [
-          "dimension",
-          "status"
-        ],
-        "type": "object"
-      },
-      "type": "array"
-    },
-    "effect": {
-      "additionalProperties": true,
-      "type": "object"
-    },
-    "metric": {
-      "type": "string"
-    }
-  },
-  "required": [
-    "metric",
-    "analysis",
-    "dimensions"
-  ],
-  "type": "object"
-}

changedOutput schema / required

Previous value: -[
-  "metric",
-  "period_a",
-  "period_b",
-  "period_a_stats",
-  "period_b_stats",
-  "claim",
-  "period_a_evidence",
-  "period_b_evidence",
-  "evidence_profile",
-  "claim_decision"
-]New value: +[
+  "metric",
+  "period_a",
+  "period_b",
+  "period_a_stats",
+  "period_b_stats",
+  "claim",
+  "period_a_evidence",
+  "period_b_evidence"
+]

Changed10 schema fields changedv1.0.26Sep 25, 2026

addedOutput schema / properties / claim

Added value: +{
+  "description": "Evidence and decision for the period comparison claim; read claim.decision before reporting it.",
+  "properties": {
+    "decision": {
+      "description": "How strongly this claim may be stated. tier is insufficient, suggestive, detectable_not_meaningful or supported; every entry in must_state has to be mentioned when reporting it.",
+      "properties": {
+        "must_state": {
+          "items": {
+            "type": "string"
+          },
+          "type": "array"
+        },
+        "permitted_phrasing_class": {
+          "type": "string"
+        },
+        "template": {
+          "type": "string"
+        },
+        "tier": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "tier",
+        "permitted_phrasing_class",
+        "must_state",
+        "template"
+      ],
+      "type": "object"
+    },
+    "evidence_a": {
+      "description": "Descriptive data coverage behind the first source.",
+      "properties": {
+        "confidence": {
+          "type": "string"
+        },
+        "coverage_ratio": {
+          "type": "number"
+        },
+        "expected_days": {
+          "type": "integer"
+        },
+        "freshness_days": {
+          "anyOf": [
+            {
+              "type": "integer"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null
+        },
+        "gaps": {
+          "items": {
+            "properties": {
+              "days": {
+                "type": "integer"
+              },
+              "end": {
+                "type": "string"
+              },
+              "start": {
+                "type": "string"
+              }
+            },
+            "required": [
+              "start",
+              "end",
+              "days"
+            ],
+            "type": "object"
+          },
+          "type": "array"
+        },
+        "measurement_count": {
+          "type": "integer"
+        },
+        "missing_days": {
+          "type": "integer"
+        },
+        "observed_days": {
+          "type": "integer"
+        },
+        "observed_end": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null
+        },
+        "observed_start": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null
+        },
+        "recent_gap_days": {
+          "type": "integer"
+        },
+        "requested_end": {
+          "type": "string"
+        },
+        "requested_start": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "requested_start",
+        "requested_end",
+        "expected_days",
+        "observed_days",
+        "coverage_ratio",
+        "missing_days",
+        "measurement_count",
+        "gaps",
+        "recent_gap_days",
+        "confidence"
+      ],
+      "type": "object"
+    },
+    "evidence_b": {
+      "description": "Descriptive data coverage behind the second source.",
+      "properties": {
+        "confidence": {
+          "type": "string"
+        },
+        "coverage_ratio": {
+          "type": "number"
+        },
+        "expected_days": {
+          "type": "integer"
+        },
+        "freshness_days": {
+          "anyOf": [
+            {
+              "type": "integer"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null
+        },
+        "gaps": {
+          "items": {
+            "properties": {
+              "days": {
+                "type": "integer"
+              },
+              "end": {
+                "type": "string"
+              },
+              "start": {
+                "type": "string"
+              }
+            },
+            "required": [
+              "start",
+              "end",
+              "days"
+            ],
+            "type": "object"
+          },
+          "type": "array"
+        },
+        "measurement_count": {
+          "type": "integer"
+        },
+        "missing_days": {
+          "type": "integer"
+        },
+        "observed_days": {
+          "type": "integer"
+        },
+        "observed_end": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null
+        },
+        "observed_start": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null
+        },
+        "recent_gap_days": {
+          "type": "integer"
+        },
+        "requested_end": {
+          "type": "string"
+        },
+        "requested_start": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "requested_start",
+        "requested_end",
+        "expected_days",
+        "observed_days",
+        "coverage_ratio",
+        "missing_days",
+        "measurement_count",
+        "gaps",
+        "recent_gap_days",
+        "confidence"
+      ],
+      "type": "object"
+    },
+    "profile": {
+      "description": "Per-dimension evidence quality behind this claim (sample, temporal, missingness, ...), assessed jointly across both sources where relevant. Dimensions without an evaluator yet are 'not_assessed' and cap the claim, never count as adequate.",
+      "properties": {
+        "analysis": {
+          "type": "string"
+        },
+        "dimensions": {
+          "items": {
+            "properties": {
+              "can_block": {
+                "default": true,
+                "type": "boolean"
+              },
+              "details": {
+                "additionalProperties": true,
+                "type": "object"
+              },
+              "dimension": {
+                "enum": [
+                  "sample",
+                  "temporal",
+                  "robustness",
+                  "missingness",
+                  "practical",
+                  "measurement_validity",
+                  "provenance"
+                ],
+                "type": "string"
+              },
+              "reason_codes": {
+                "items": {
+                  "type": "string"
+                },
+                "type": "array"
+              },
+              "status": {
+                "enum": [
+                  "adequate",
+                  "negligible",
+                  "not_assessed",
+                  "weak",
+                  "concern",
+                  "blocking"
+                ],
+                "type": "string"
+              }
+            },
+            "required": [
+              "dimension",
+              "status"
+            ],
+            "type": "object"
+          },
+          "type": "array"
+        },
+        "effect": {
+          "additionalProperties": true,
+          "type": "object"
+        },
+        "metric": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "metric",
+        "analysis",
+        "dimensions"
+      ],
+      "type": "object"
+    }
+  },
+  "required": [
+    "evidence_a",
+    "evidence_b",
+    "profile",
+    "decision"
+  ],
+  "type": "object"
+}

addedOutput schema / properties / claim_decision / deprecated
```
Added value: +true
```

changedOutput schema / properties / claim_decision / description

Previous value: -"How strongly this result may be stated. tier is insufficient, suggestive, detectable_not_meaningful or supported; every entry in must_state has to be mentioned when reporting it."New value: +"DEPRECATED: identical to claim.decision. Use claim.decision instead."

addedOutput schema / properties / evidence_profile / deprecated
```
Added value: +true
```

changedOutput schema / properties / evidence_profile / description

Previous value: -"Per-dimension evidence quality behind this result (sample, temporal, missingness, ...). Dimensions without an evaluator yet are 'not_assessed' and cap the claim, never count as adequate."New value: +"DEPRECATED: identical to claim.profile. Use claim.decision instead."

addedOutput schema / properties / period_a_evidence / deprecated
```
Added value: +true
```

changedOutput schema / properties / period_a_evidence / description

Previous value: -"Coverage/quality of the data a single-metric analytical result is\nbased on. See evidence.build_evidence for how each field is computed."New value: +"DEPRECATED: identical to claim.evidence_a. Use claim.decision, not a standalone confidence field."

addedOutput schema / properties / period_b_evidence / deprecated
```
Added value: +true
```

changedOutput schema / properties / period_b_evidence / description

Previous value: -"Coverage/quality of the data a single-metric analytical result is\nbased on. See evidence.build_evidence for how each field is computed."New value: +"DEPRECATED: identical to claim.evidence_b. Use claim.decision, not a standalone confidence field."

changedOutput schema / required

Previous value: -[
-  "evidence_profile",
-  "claim_decision",
-  "metric",
-  "period_a",
-  "period_b",
-  "period_a_stats",
-  "period_b_stats",
-  "period_a_evidence",
-  "period_b_evidence"
-]New value: +[
+  "metric",
+  "period_a",
+  "period_b",
+  "period_a_stats",
+  "period_b_stats",
+  "claim",
+  "period_a_evidence",
+  "period_b_evidence",
+  "evidence_profile",
+  "claim_decision"
+]

Changed11 schema fields changedv1.0.23Sep 24, 2026

removedOutput schema / properties / claim_decision / anyOf

Removed value: -[
-  {
-    "properties": {
-      "must_state": {
-        "items": {
-          "type": "string"
-        },
-        "type": "array"
-      },
-      "permitted_phrasing_class": {
-        "type": "string"
-      },
-      "template": {
-        "type": "string"
-      },
-      "tier": {
-        "type": "string"
-      }
-    },
-    "required": [
-      "tier",
-      "permitted_phrasing_class",
-      "must_state",
-      "template"
-    ],
-    "type": "object"
-  },
-  {
-    "type": "null"
-  }
-]

removedOutput schema / properties / claim_decision / default
```
Removed value: -null
```

addedOutput schema / properties / claim_decision / properties

Added value: +{
+  "must_state": {
+    "items": {
+      "type": "string"
+    },
+    "type": "array"
+  },
+  "permitted_phrasing_class": {
+    "type": "string"
+  },
+  "template": {
+    "type": "string"
+  },
+  "tier": {
+    "type": "string"
+  }
+}

addedOutput schema / properties / claim_decision / required

Added value: +[
+  "tier",
+  "permitted_phrasing_class",
+  "must_state",
+  "template"
+]

addedOutput schema / properties / claim_decision / type
```
Added value: +"object"
```

removedOutput schema / properties / evidence_profile / anyOf

Removed value: -[
-  {
-    "properties": {
-      "analysis": {
-        "type": "string"
-      },
-      "dimensions": {
-        "items": {
-          "properties": {
-            "can_block": {
-              "default": true,
-              "type": "boolean"
-            },
-            "details": {
-              "additionalProperties": true,
-              "type": "object"
-            },
-            "dimension": {
-              "enum": [
-                "sample",
-                "temporal",
-                "robustness",
-                "missingness",
-                "practical",
-                "measurement_validity",
-                "provenance"
-              ],
-              "type": "string"
-            },
-            "reason_codes": {
-              "items": {
-                "type": "string"
-              },
-              "type": "array"
-            },
-            "status": {
-              "enum": [
-                "adequate",
-                "negligible",
-                "not_assessed",
-                "weak",
-                "concern",
-                "blocking"
-              ],
-              "type": "string"
-            }
-          },
-          "required": [
-            "dimension",
-            "status"
-          ],
-          "type": "object"
-        },
-        "type": "array"
-      },
-      "effect": {
-        "additionalProperties": true,
-        "type": "object"
-      },
-      "metric": {
-        "type": "string"
-      }
-    },
-    "required": [
-      "metric",
-      "analysis",
-      "dimensions"
-    ],
-    "type": "object"
-  },
-  {
-    "type": "null"
-  }
-]

removedOutput schema / properties / evidence_profile / default
```
Removed value: -null
```

addedOutput schema / properties / evidence_profile / properties

Added value: +{
+  "analysis": {
+    "type": "string"
+  },
+  "dimensions": {
+    "items": {
+      "properties": {
+        "can_block": {
+          "default": true,
+          "type": "boolean"
+        },
+        "details": {
+          "additionalProperties": true,
+          "type": "object"
+        },
+        "dimension": {
+          "enum": [
+            "sample",
+            "temporal",
+            "robustness",
+            "missingness",
+            "practical",
+            "measurement_validity",
+            "provenance"
+          ],
+          "type": "string"
+        },
+        "reason_codes": {
+          "items": {
+            "type": "string"
+          },
+          "type": "array"
+        },
+        "status": {
+          "enum": [
+            "adequate",
+            "negligible",
+            "not_assessed",
+            "weak",
+            "concern",
+            "blocking"
+          ],
+          "type": "string"
+        }
+      },
+      "required": [
+        "dimension",
+        "status"
+      ],
+      "type": "object"
+    },
+    "type": "array"
+  },
+  "effect": {
+    "additionalProperties": true,
+    "type": "object"
+  },
+  "metric": {
+    "type": "string"
+  }
+}

addedOutput schema / properties / evidence_profile / required

Added value: +[
+  "metric",
+  "analysis",
+  "dimensions"
+]

addedOutput schema / properties / evidence_profile / type
```
Added value: +"object"
```

changedOutput schema / required

Previous value: -[
-  "metric",
-  "period_a",
-  "period_b",
-  "period_a_stats",
-  "period_b_stats",
-  "period_a_evidence",
-  "period_b_evidence"
-]New value: +[
+  "evidence_profile",
+  "claim_decision",
+  "metric",
+  "period_a",
+  "period_b",
+  "period_a_stats",
+  "period_b_stats",
+  "period_a_evidence",
+  "period_b_evidence"
+]

Changed2 schema fields changedv1.0.20Sep 20, 2026

addedOutput schema / properties / claim_decision

Added value: +{
+  "anyOf": [
+    {
+      "properties": {
+        "must_state": {
+          "items": {
+            "type": "string"
+          },
+          "type": "array"
+        },
+        "permitted_phrasing_class": {
+          "type": "string"
+        },
+        "template": {
+          "type": "string"
+        },
+        "tier": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "tier",
+        "permitted_phrasing_class",
+        "must_state",
+        "template"
+      ],
+      "type": "object"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "description": "How strongly this result may be stated. tier is insufficient, suggestive, detectable_not_meaningful or supported; every entry in must_state has to be mentioned when reporting it."
+}

addedOutput schema / properties / evidence_profile

Added value: +{
+  "anyOf": [
+    {
+      "properties": {
+        "analysis": {
+          "type": "string"
+        },
+        "dimensions": {
+          "items": {
+            "properties": {
+              "can_block": {
+                "default": true,
+                "type": "boolean"
+              },
+              "details": {
+                "additionalProperties": true,
+                "type": "object"
+              },
+              "dimension": {
+                "enum": [
+                  "sample",
+                  "temporal",
+                  "robustness",
+                  "missingness",
+                  "practical",
+                  "measurement_validity",
+                  "provenance"
+                ],
+                "type": "string"
+              },
+              "reason_codes": {
+                "items": {
+                  "type": "string"
+                },
+                "type": "array"
+              },
+              "status": {
+                "enum": [
+                  "adequate",
+                  "negligible",
+                  "not_assessed",
+                  "weak",
+                  "concern",
+                  "blocking"
+                ],
+                "type": "string"
+              }
+            },
+            "required": [
+              "dimension",
+              "status"
+            ],
+            "type": "object"
+          },
+          "type": "array"
+        },
+        "effect": {
+          "additionalProperties": true,
+          "type": "object"
+        },
+        "metric": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "metric",
+        "analysis",
+        "dimensions"
+      ],
+      "type": "object"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "description": "Per-dimension evidence quality behind this result (sample, temporal, missingness, ...). Dimensions without an evaluator yet are 'not_assessed' and cap the claim, never count as adequate."
+}

Changed3 schema fields changedSep 15, 2026

addedOutput schema / properties / period_a_evidence

Added value: +{
+  "description": "Coverage/quality of the data a single-metric analytical result is\nbased on. See evidence.build_evidence for how each field is computed.",
+  "properties": {
+    "confidence": {
+      "type": "string"
+    },
+    "coverage_ratio": {
+      "type": "number"
+    },
+    "expected_days": {
+      "type": "integer"
+    },
+    "freshness_days": {
+      "anyOf": [
+        {
+          "type": "integer"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null
+    },
+    "gaps": {
+      "items": {
+        "properties": {
+          "days": {
+            "type": "integer"
+          },
+          "end": {
+            "type": "string"
+          },
+          "start": {
+            "type": "string"
+          }
+        },
+        "required": [
+          "start",
+          "end",
+          "days"
+        ],
+        "type": "object"
+      },
+      "type": "array"
+    },
+    "measurement_count": {
+      "type": "integer"
+    },
+    "missing_days": {
+      "type": "integer"
+    },
+    "observed_days": {
+      "type": "integer"
+    },
+    "observed_end": {
+      "anyOf": [
+        {
+          "type": "string"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null
+    },
+    "observed_start": {
+      "anyOf": [
+        {
+          "type": "string"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null
+    },
+    "recent_gap_days": {
+      "type": "integer"
+    },
+    "requested_end": {
+      "type": "string"
+    },
+    "requested_start": {
+      "type": "string"
+    }
+  },
+  "required": [
+    "requested_start",
+    "requested_end",
+    "expected_days",
+    "observed_days",
+    "coverage_ratio",
+    "missing_days",
+    "measurement_count",
+    "gaps",
+    "recent_gap_days",
+    "confidence"
+  ],
+  "type": "object"
+}

addedOutput schema / properties / period_b_evidence

Added value: +{
+  "description": "Coverage/quality of the data a single-metric analytical result is\nbased on. See evidence.build_evidence for how each field is computed.",
+  "properties": {
+    "confidence": {
+      "type": "string"
+    },
+    "coverage_ratio": {
+      "type": "number"
+    },
+    "expected_days": {
+      "type": "integer"
+    },
+    "freshness_days": {
+      "anyOf": [
+        {
+          "type": "integer"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null
+    },
+    "gaps": {
+      "items": {
+        "properties": {
+          "days": {
+            "type": "integer"
+          },
+          "end": {
+            "type": "string"
+          },
+          "start": {
+            "type": "string"
+          }
+        },
+        "required": [
+          "start",
+          "end",
+          "days"
+        ],
+        "type": "object"
+      },
+      "type": "array"
+    },
+    "measurement_count": {
+      "type": "integer"
+    },
+    "missing_days": {
+      "type": "integer"
+    },
+    "observed_days": {
+      "type": "integer"
+    },
+    "observed_end": {
+      "anyOf": [
+        {
+          "type": "string"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null
+    },
+    "observed_start": {
+      "anyOf": [
+        {
+          "type": "string"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null
+    },
+    "recent_gap_days": {
+      "type": "integer"
+    },
+    "requested_end": {
+      "type": "string"
+    },
+    "requested_start": {
+      "type": "string"
+    }
+  },
+  "required": [
+    "requested_start",
+    "requested_end",
+    "expected_days",
+    "observed_days",
+    "coverage_ratio",
+    "missing_days",
+    "measurement_count",
+    "gaps",
+    "recent_gap_days",
+    "confidence"
+  ],
+  "type": "object"
+}

changedOutput schema / required

Previous value: -[
-  "metric",
-  "period_a",
-  "period_b",
-  "period_a_stats",
-  "period_b_stats"
-]New value: +[
+  "metric",
+  "period_a",
+  "period_b",
+  "period_a_stats",
+  "period_b_stats",
+  "period_a_evidence",
+  "period_b_evidence"
+]

Addedv1.0.16Sep 15, 2026
Removedv1.0.15Sep 15, 2026
Addedv1.0.11Sep 13, 2026

TDQS

A4.3/5.0

Behavior4/5

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed world), yet the description adds genuinely new behavioral context: each range is summarized with its own baseline first, and a privacy note explains that returned data flows to the calling client's model. It stops short of documenting the date format or any limits on range size.

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?

Front-loaded with purpose, then cleanly bulleted when/when-not routing, then the privacy caveat last. The privacy paragraph is long but is a genuine disclosure rather than filler; overall the structure earns its length.

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

Completeness4/5

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

An output schema exists, so return values need not be explained, and the routing plus privacy coverage make the definition self-sufficient for selection. The only missing piece an agent still needs is the required date format for the four period parameters.

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

Parameters3/5

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

Schema coverage is only 20%: the four period_*_start/end parameters have no schema descriptions at all, and the description does not give a date format or syntax for them. It does add useful semantics (ranges may be any length and need not be adjacent or equal, each gets its own baseline) and the metric enum is documented, but the undocumented date params leave a real gap.

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

Purpose5/5

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

The first sentence gives a specific verb (compare) and resource (one metric's average) plus the exact scope (two date ranges), with concrete examples. It is immediately distinguishable from siblings like calculate_metric_trend and get_baseline.

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

Usage Guidelines5/5

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

Explicit 'Use this tool when' and 'Do not use this tool when' sections that name the alternative sibling for each exclusion (calculate_metric_trend for one continuous window, get_baseline for single-window norms). Nothing is left to inference.

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

Compare two periods

Instructions

Input Schema

Output Schema

Schema Changelog

TDQS

Other Tools