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Log a daily metric

log_daily_metric

DestructiveIdempotent

Record daily health metrics like mood, steps, sleep, and weight for a specific date. Creates the day's entry if missing while preserving other already-logged values.

Instructions

Record one or more health metrics for a single day, creating that day's row if it doesn't already have one.

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.

Only the metrics you pass are written — anything left as null is not touched, so logging just today's mood doesn't erase today's steps if they were set earlier. To undo a value logged by mistake, use clear_metric rather than trying to overwrite it with a placeholder.

Use this tool when:

the user is recording a simple day-level value for one of the nine fixed metrics below (e.g. "log my weight as 82 kg", "I walked 8,000 steps today").

Do not use this tool when:

the observation needs its own timestamp/source, or the day may have more than one reading of the same metric -> use log_measurement instead.
it's a workout/exercise session -> use log_workout_session instead (workout_minutes here is just the daily total, not the session itself).

Input Schema

TableJSON Schema

Name	Required	Description
`date`	Yes	The day to log, formatted YYYY-MM-DD.
`mood`	No	Mood rating on a 1-10 scale.
`steps`	No	Step count for the day. 0-200,000.
`hrv_ms`	No	Heart rate variability in milliseconds. 0-300.
`water_ml`	No	Water intake in millilitres. 0-10,000.
`weight_kg`	No	Body weight in kilograms. 1-500.
`heart_rate`	No	Non-resting heart rate reading in bpm. 20-250.
`sleep_hours`	No	Hours of sleep. 0-24.
`workout_minutes`	No	Minutes of exercise. 0-1,440.
`resting_heart_rate`	No	Resting heart rate in bpm. 20-250.

Output Schema

TableJSON Schema

Name	Required	Description	Default
`row`	Yes
`logged`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed15 schema fields changedv1.0.16Sep 15, 2026

addedInput schema / properties / date / description

Added value: +"The day to log, formatted YYYY-MM-DD."

addedInput schema / properties / heart_rate

Added value: +{
+  "anyOf": [
+    {
+      "type": "integer"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "description": "Non-resting heart rate reading in bpm. 20-250."
+}

addedInput schema / properties / hrv_ms

Added value: +{
+  "anyOf": [
+    {
+      "type": "number"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "description": "Heart rate variability in milliseconds. 0-300."
+}

addedInput schema / properties / mood

Added value: +{
+  "anyOf": [
+    {
+      "type": "integer"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "description": "Mood rating on a 1-10 scale."
+}

addedInput schema / properties / resting_heart_rate / description
```
Added value: +"Resting heart rate in bpm. 20-250."
```
addedInput schema / properties / sleep_hours / description
```
Added value: +"Hours of sleep. 0-24."
```

addedInput schema / properties / steps / description

Added value: +"Step count for the day. 0-200,000."

addedInput schema / properties / water_ml

Added value: +{
+  "anyOf": [
+    {
+      "type": "integer"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "description": "Water intake in millilitres. 0-10,000."
+}

addedInput schema / properties / weight_kg

Added value: +{
+  "anyOf": [
+    {
+      "type": "number"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "description": "Body weight in kilograms. 1-500."
+}

addedInput schema / properties / workout_minutes

Added value: +{
+  "anyOf": [
+    {
+      "type": "integer"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "description": "Minutes of exercise. 0-1,440."
+}

addedOutput schema / properties / logged

Added value: +{
+  "additionalProperties": {
+    "anyOf": [
+      {
+        "type": "integer"
+      },
+      {
+        "type": "number"
+      }
+    ]
+  },
+  "type": "object"
+}

removedOutput schema / properties / result

Removed value: -{
-  "type": "string"
-}

addedOutput schema / properties / row

Added value: +{
+  "properties": {
+    "date": {
+      "type": "string"
+    },
+    "heart_rate": {
+      "anyOf": [
+        {
+          "type": "integer"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null
+    },
+    "hrv_ms": {
+      "anyOf": [
+        {
+          "type": "number"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null
+    },
+    "mood": {
+      "anyOf": [
+        {
+          "type": "integer"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null
+    },
+    "resting_heart_rate": {
+      "anyOf": [
+        {
+          "type": "integer"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null
+    },
+    "sleep_hours": {
+      "anyOf": [
+        {
+          "type": "number"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null
+    },
+    "steps": {
+      "anyOf": [
+        {
+          "type": "integer"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null
+    },
+    "water_ml": {
+      "anyOf": [
+        {
+          "type": "integer"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null
+    },
+    "weight_kg": {
+      "anyOf": [
+        {
+          "type": "number"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null
+    },
+    "workout_minutes": {
+      "anyOf": [
+        {
+          "type": "integer"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null
+    }
+  },
+  "required": [
+    "date"
+  ],
+  "type": "object"
+}

changedOutput schema / required

Previous value: -[
-  "result"
-]New value: +[
+  "logged",
+  "row"
+]

removedOutput schema / x-fastmcp-wrap-result
```
Removed value: -true
```

Changed15 schema fields changedv1.0.15Sep 15, 2026

removedInput schema / properties / date / description

Removed value: -"The day to log, formatted YYYY-MM-DD."

removedInput schema / properties / heart_rate

Removed value: -{
-  "anyOf": [
-    {
-      "type": "integer"
-    },
-    {
-      "type": "null"
-    }
-  ],
-  "default": null,
-  "description": "Non-resting heart rate reading in bpm. 20-250."
-}

removedInput schema / properties / hrv_ms

Removed value: -{
-  "anyOf": [
-    {
-      "type": "number"
-    },
-    {
-      "type": "null"
-    }
-  ],
-  "default": null,
-  "description": "Heart rate variability in milliseconds. 0-300."
-}

removedInput schema / properties / mood

Removed value: -{
-  "anyOf": [
-    {
-      "type": "integer"
-    },
-    {
-      "type": "null"
-    }
-  ],
-  "default": null,
-  "description": "Mood rating on a 1-10 scale."
-}

removedInput schema / properties / resting_heart_rate / description
```
Removed value: -"Resting heart rate in bpm. 20-250."
```
removedInput schema / properties / sleep_hours / description
```
Removed value: -"Hours of sleep. 0-24."
```

removedInput schema / properties / steps / description

Removed value: -"Step count for the day. 0-200,000."

removedInput schema / properties / water_ml

Removed value: -{
-  "anyOf": [
-    {
-      "type": "integer"
-    },
-    {
-      "type": "null"
-    }
-  ],
-  "default": null,
-  "description": "Water intake in millilitres. 0-10,000."
-}

removedInput schema / properties / weight_kg

Removed value: -{
-  "anyOf": [
-    {
-      "type": "number"
-    },
-    {
-      "type": "null"
-    }
-  ],
-  "default": null,
-  "description": "Body weight in kilograms. 1-500."
-}

removedInput schema / properties / workout_minutes

Removed value: -{
-  "anyOf": [
-    {
-      "type": "integer"
-    },
-    {
-      "type": "null"
-    }
-  ],
-  "default": null,
-  "description": "Minutes of exercise. 0-1,440."
-}

removedOutput schema / properties / logged

Removed value: -{
-  "additionalProperties": {
-    "anyOf": [
-      {
-        "type": "integer"
-      },
-      {
-        "type": "number"
-      }
-    ]
-  },
-  "type": "object"
-}

addedOutput schema / properties / result
```
Added value: +{
+  "type": "string"
+}
```

removedOutput schema / properties / row

Removed value: -{
-  "properties": {
-    "date": {
-      "type": "string"
-    },
-    "heart_rate": {
-      "anyOf": [
-        {
-          "type": "integer"
-        },
-        {
-          "type": "null"
-        }
-      ],
-      "default": null
-    },
-    "hrv_ms": {
-      "anyOf": [
-        {
-          "type": "number"
-        },
-        {
-          "type": "null"
-        }
-      ],
-      "default": null
-    },
-    "mood": {
-      "anyOf": [
-        {
-          "type": "integer"
-        },
-        {
-          "type": "null"
-        }
-      ],
-      "default": null
-    },
-    "resting_heart_rate": {
-      "anyOf": [
-        {
-          "type": "integer"
-        },
-        {
-          "type": "null"
-        }
-      ],
-      "default": null
-    },
-    "sleep_hours": {
-      "anyOf": [
-        {
-          "type": "number"
-        },
-        {
-          "type": "null"
-        }
-      ],
-      "default": null
-    },
-    "steps": {
-      "anyOf": [
-        {
-          "type": "integer"
-        },
-        {
-          "type": "null"
-        }
-      ],
-      "default": null
-    },
-    "water_ml": {
-      "anyOf": [
-        {
-          "type": "integer"
-        },
-        {
-          "type": "null"
-        }
-      ],
-      "default": null
-    },
-    "weight_kg": {
-      "anyOf": [
-        {
-          "type": "number"
-        },
-        {
-          "type": "null"
-        }
-      ],
-      "default": null
-    },
-    "workout_minutes": {
-      "anyOf": [
-        {
-          "type": "integer"
-        },
-        {
-          "type": "null"
-        }
-      ],
-      "default": null
-    }
-  },
-  "required": [
-    "date"
-  ],
-  "type": "object"
-}

changedOutput schema / required

Previous value: -[
-  "logged",
-  "row"
-]New value: +[
+  "result"
+]

addedOutput schema / x-fastmcp-wrap-result
```
Added value: +true
```

Changed4 schema fields changedv1.0.11Sep 13, 2026

addedInput schema / properties / heart_rate

Added value: +{
+  "anyOf": [
+    {
+      "type": "integer"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "description": "Non-resting heart rate reading in bpm. 20-250."
+}

addedInput schema / properties / hrv_ms

Added value: +{
+  "anyOf": [
+    {
+      "type": "number"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "description": "Heart rate variability in milliseconds. 0-300."
+}

addedOutput schema / properties / row / properties / heart_rate

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

addedOutput schema / properties / row / properties / hrv_ms

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

Changed5 schema fields changedv1.0.8Sep 7, 2026

addedOutput schema / properties / logged

Added value: +{
+  "additionalProperties": {
+    "anyOf": [
+      {
+        "type": "integer"
+      },
+      {
+        "type": "number"
+      }
+    ]
+  },
+  "type": "object"
+}

removedOutput schema / properties / result

Removed value: -{
-  "type": "string"
-}

addedOutput schema / properties / row

Added value: +{
+  "properties": {
+    "date": {
+      "type": "string"
+    },
+    "mood": {
+      "anyOf": [
+        {
+          "type": "integer"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null
+    },
+    "resting_heart_rate": {
+      "anyOf": [
+        {
+          "type": "integer"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null
+    },
+    "sleep_hours": {
+      "anyOf": [
+        {
+          "type": "number"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null
+    },
+    "steps": {
+      "anyOf": [
+        {
+          "type": "integer"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null
+    },
+    "water_ml": {
+      "anyOf": [
+        {
+          "type": "integer"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null
+    },
+    "weight_kg": {
+      "anyOf": [
+        {
+          "type": "number"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null
+    },
+    "workout_minutes": {
+      "anyOf": [
+        {
+          "type": "integer"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null
+    }
+  },
+  "required": [
+    "date"
+  ],
+  "type": "object"
+}

changedOutput schema / required

Previous value: -[
-  "result"
-]New value: +[
+  "logged",
+  "row"
+]

removedOutput schema / x-fastmcp-wrap-result
```
Removed value: -true
```

Addedv1.0.4Sep 2, 2026

TDQS

A4.7/5.0

Behavior5/5

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

Beyond the annotations, the description discloses the crucial merge behavior: null metrics are untouched and only passed metrics are written. It also adds a privacy note about data becoming part of the conversation and suggests clear_metric for undo. These are meaningful behavioral details that do not contradict 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.

Conciseness5/5

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

The description is well-structured with a front-loaded core statement, a privacy section, a merge-behavior section, and explicit usage conditions. Despite its length, every section addresses a real agent decision and no sentence is 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?

For a mutating tool with 10 parameters, the description covers sibling selection, partial-update semantics, privacy implications, and recovery via clear_metric. An output schema exists, so return-value details are not necessary. The tool is fully specified for correct invocation.

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?

The schema already describes all 10 parameters with units and ranges, so the baseline is 3. The description adds context like 'workout_minutes here is just the daily total' and the null-not-touched rule, but does not need to repeat the schema's per-parameter details.

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 description opens with a specific verb and resource: 'Record one or more health metrics for a single day', and explains the row-creation behavior. It also explicitly distinguishes itself from siblings like log_measurement and log_workout_session, so an agent can tell them apart without inspecting schemas.

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?

The description has clear 'Use this tool when' and 'Do not use this tool when' sections with concrete conditions and named alternatives. It routes timestamped readings to log_measurement and workout sessions to log_workout_session, leaving no ambiguity about selection.

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

Log a daily metric

Instructions

Input Schema

Output Schema

Schema Changelog

TDQS

Other Tools