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Calculate metric trend

calculate_metric_trend

Read-onlyIdempotent

Fit a simple straight-line trend to one metric over a window and report its direction, slope (change per day), and r_squared (how well a straight line actually fits — low r_squared means "noisy," not "flat").

Instructions

Use this tool when:

the user asks whether one metric is trending up/down/flat over a continuous window (e.g. "is my weight trending down?", "how has my HRV changed?").

Do not use this tool when:

the user wants two specific, separately-defined ranges compared (e.g. "this month vs last month") rather than a single continuous slope -> use compare_metric_periods instead.
the user asks what's typical/normal rather than which direction it's moving -> use get_baseline instead.
the user asks about isolated unusual days rather than an overall direction -> use detect_metric_anomalies 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

Name	Required	Description
`metric`	Yes	One of steps, sleep_hours, resting_heart_rate, weight_kg, workout_minutes, mood, water_ml, heart_rate, hrv_ms.
`end_date`	No	Last day to include, formatted YYYY-MM-DD. Defaults to today.
`start_date`	No	First day to include, formatted YYYY-MM-DD. Defaults to 30 days before end_date.

Output Schema

Name	Required	Description
`claim`	Yes	Evidence and decision for the trend claim; read claim.decision before reporting it.
`range`	Yes
`trend`	Yes
`metric`	Yes
`evidence`	Yes	DEPRECATED: identical to claim.evidence. Use claim.decision, not evidence.confidence.
`data_health`	No	Whether the data behind this result is complete, current and trustworthy.

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv1.0.30Oct 13, 2026

addedOutput schema / properties / data_health

Added value: +{
+  "anyOf": [
+    {
+      "description": "Data-quality state behind one result (not a medical or statistical confidence score). status is one of\nVALID, VALID_WITH_GAPS, MIXED_SOURCES, INSUFFICIENT_DATA, STALE, IMPORT_INCOMPLETE; reasons lists every\ncondition that\napplies. See data_health.compose_data_health for how it is decided.",
+      "properties": {
+        "completeness": {
+          "properties": {
+            "coverage_ratio": {
+              "type": "number"
+            },
+            "expected_days": {
+              "type": "integer"
+            },
+            "missing_days": {
+              "type": "integer"
+            },
+            "observed_days": {
+              "type": "integer"
+            }
+          },
+          "required": [
+            "expected_days",
+            "observed_days",
+            "coverage_ratio",
+            "missing_days"
+          ],
+          "type": "object"
+        },
+        "coverage": {
+          "properties": {
+            "end": {
+              "anyOf": [
+                {
+                  "type": "string"
+                },
+                {
+                  "type": "null"
+                }
+              ],
+              "default": null
+            },
+            "requested_end": {
+              "type": "string"
+            },
+            "requested_start": {
+              "type": "string"
+            },
+            "start": {
+              "anyOf": [
+                {
+                  "type": "string"
+                },
+                {
+                  "type": "null"
+                }
+              ],
+              "default": null
+            }
+          },
+          "required": [
+            "requested_start",
+            "requested_end"
+          ],
+          "type": "object"
+        },
+        "freshness": {
+          "properties": {
+            "age_days": {
+              "anyOf": [
+                {
+                  "type": "integer"
+                },
+                {
+                  "type": "null"
+                }
+              ],
+              "default": null,
+              "description": "Days from the latest observation to the end of the requested window."
+            },
+            "dataset_days_behind": {
+              "anyOf": [
+                {
+                  "type": "integer"
+                },
+                {
+                  "type": "null"
+                }
+              ],
+              "default": null,
+              "description": "Days from the dataset's latest data (any metric) to today."
+            },
+            "latest_data": {
+              "anyOf": [
+                {
+                  "type": "string"
+                },
+                {
+                  "type": "null"
+                }
+              ],
+              "default": null
+            }
+          },
+          "type": "object"
+        },
+        "gaps": {
+          "items": {
+            "properties": {
+              "days": {
+                "type": "integer"
+              },
+              "end": {
+                "type": "string"
+              },
+              "start": {
+                "type": "string"
+              }
+            },
+            "required": [
+              "start",
+              "end",
+              "days"
+            ],
+            "type": "object"
+          },
+          "type": "array"
+        },
+        "last_import": {
+          "anyOf": [
+            {
+              "properties": {
+                "finished_at": {
+                  "anyOf": [
+                    {
+                      "type": "string"
+                    },
+                    {
+                      "type": "null"
+                    }
+                  ],
+                  "default": null
+                },
+                "importer": {
+                  "type": "string"
+                },
+                "source_file": {
+                  "anyOf": [
+                    {
+                      "type": "string"
+                    },
+                    {
+                      "type": "null"
+                    }
+                  ],
+                  "default": null
+                },
+                "status": {
+                  "type": "string"
+                }
+              },
+              "required": [
+                "importer",
+                "status"
+              ],
+              "type": "object"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null
+        },
+        "last_successful_import": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null
+        },
+        "observations": {
+          "description": "Number of daily values the result is computed from.",
+          "type": "integer"
+        },
+        "reasons": {
+          "items": {
+            "type": "string"
+          },
+          "type": "array"
+        },
+        "status": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "status",
+        "reasons",
+        "freshness",
+        "coverage",
+        "completeness",
+        "gaps",
+        "observations"
+      ],
+      "type": "object"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "description": "Whether the data behind this result is complete, current and trustworthy."
+}

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",
-  "range",
-  "trend",
-  "claim",
-  "evidence",
-  "evidence_profile",
-  "claim_decision"
-]New value: +[
+  "metric",
+  "range",
+  "trend",
+  "claim",
+  "evidence"
+]

Changed8 schema fields changedv1.0.26Sep 25, 2026

addedOutput schema / properties / claim

Added value: +{
+  "description": "Evidence and decision for the trend 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": {
+      "description": "Descriptive data coverage behind this claim.",
+      "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, ...). 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",
+    "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 / deprecated
```
Added value: +true
```

changedOutput schema / properties / 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. Use claim.decision, not evidence.confidence."

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."

changedOutput schema / required

Previous value: -[
-  "evidence_profile",
-  "claim_decision",
-  "metric",
-  "range",
-  "trend",
-  "evidence"
-]New value: +[
+  "metric",
+  "range",
+  "trend",
+  "claim",
+  "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",
-  "range",
-  "trend",
-  "evidence"
-]New value: +[
+  "evidence_profile",
+  "claim_decision",
+  "metric",
+  "range",
+  "trend",
+  "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."
+}

Changed1 schema field changedv1.0.17Sep 16, 2026

addedOutput schema / properties / trend / properties / span_days

Added value: +{
+  "anyOf": [
+    {
+      "type": "integer"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null
+}

Changed2 schema fields changedSep 15, 2026

addedOutput schema / properties / 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",
-  "range",
-  "trend"
-]New value: +[
+  "metric",
+  "range",
+  "trend",
+  "evidence"
+]

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

TDQS

A4.4/5.0

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), so the description is not obligated to restate it — and it doesn't. It instead adds genuinely new behavioral context: the model-disclosure privacy caveat about data leaving the local SQLite into a cloud conversation, and the interpretation caveat that low r_squared means 'noisy,' not 'flat.' It stops short of describing result shape or performance characteristics, so 4 rather than 5.

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-loads the core action and return values before the routing lists, and the when/when-not blocks are scannable. The privacy paragraph is noticeably long relative to its low-frequency relevance, but it is substantive rather than filler.

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

Completeness5/5

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 no explanation, and the description still supplies the one thing the schema can't: how to read r_squared. Together with the explicit sibling routing and the privacy caveat, an agent has everything needed to select and call this tool correctly.

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 description coverage is 100%: metric's allowed values, date format YYYY-MM-DD, and both defaults are already fully documented in the schema. The description adds no syntax or format detail beyond that, so the baseline 3 applies.

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?

States a specific verb (fit a straight-line trend) and resource (one metric over a window), plus exactly what is returned: direction, slope per day, and r_squared. This lets an agent distinguish it from get_metric_history, aggregate_measurements, and the regression-adjacent siblings without opening any schema.

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?

Contains explicit 'use this tool when' and 'do not use this tool when' sections with three named alternatives (compare_metric_periods, get_baseline, detect_metric_anomalies), each tied to a concrete user-utterance trigger. Nothing about tool selection 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.

Calculate metric trend

Instructions

Input Schema

Output Schema

Schema Changelog

TDQS

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