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Log a raw measurement

log_measurement

Record a single timestamped observation—one metric, value, and time—for cases where exact time, source, or multiple same-day readings matter (e.g., blood pressure at 7 a.m., wearable heart-rate samples).

Instructions

Record a single raw observation — one metric, one value, one point in time — rather than a whole day's summary. Use this instead of log_daily_metric when the source, exact time, or the fact that there were multiple readings that day matters (e.g. three separate workouts, or a wearable's periodic heart-rate samples).

Use this tool when:

recording one timestamped observation where the exact time, source, or possibility of multiple same-day readings matters (e.g. "record my blood pressure reading from my cuff at 7am").

Do not use this tool when:

it's just a single end-of-day value for a fixed metric -> use log_daily_metric instead.
it's a workout/exercise session -> use log_workout_session 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
`unit`	No	Unit the value is in, e.g. "bpm", "kg". Optional.
`value`	Yes	The numeric reading.
`metric`	Yes	Name of the metric, e.g. "resting_heart_rate", "steps". Free-form — not limited to daily_metrics' fixed columns.
`source`	No	Where this came from, e.g. "Apple Watch", "manual". Optional.
`timestamp`	Yes	When the observation was taken, YYYY-MM-DD or a full ISO 8601 timestamp (YYYY-MM-DDTHH:MM:SS).
`source_type`	No	Category of source, e.g. "wearable", "manual", "app". Optional.

Output Schema

TableJSON Schema

Name	Required	Description	Default
`measurement`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed14 schema fields changedv1.0.16Sep 15, 2026

removedInput schema / properties / date

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

addedInput schema / properties / metric

Added value: +{
+  "description": "Name of the metric, e.g. \"resting_heart_rate\", \"steps\".\nFree-form — not limited to daily_metrics' fixed columns.",
+  "type": "string"
+}

removedInput schema / properties / metric_name
```
Removed value: -{
-  "type": "string"
-}
```

removedInput schema / properties / notes

Removed value: -{
-  "anyOf": [
-    {
-      "type": "string"
-    },
-    {
-      "type": "null"
-    }
-  ],
-  "default": null
-}

addedInput schema / properties / source

Added value: +{
+  "anyOf": [
+    {
+      "type": "string"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "description": "Where this came from, e.g. \"Apple Watch\", \"manual\". Optional."
+}

addedInput schema / properties / source_type

Added value: +{
+  "anyOf": [
+    {
+      "type": "string"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "description": "Category of source, e.g. \"wearable\", \"manual\", \"app\". Optional."
+}

addedInput schema / properties / timestamp

Added value: +{
+  "description": "When the observation was taken, YYYY-MM-DD or a full\nISO 8601 timestamp (YYYY-MM-DDTHH:MM:SS).",
+  "type": "string"
+}

addedInput schema / properties / unit / description

Added value: +"Unit the value is in, e.g. \"bpm\", \"kg\". Optional."

addedInput schema / properties / value / description
```
Added value: +"The numeric reading."
```

changedInput schema / required

Previous value: -[
-  "date",
-  "metric_name",
-  "value"
-]New value: +[
+  "timestamp",
+  "metric",
+  "value"
+]

addedOutput schema / properties / measurement

Added value: +{
+  "properties": {
+    "created_at": {
+      "type": "string"
+    },
+    "id": {
+      "type": "integer"
+    },
+    "metric": {
+      "type": "string"
+    },
+    "source": {
+      "anyOf": [
+        {
+          "type": "string"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null
+    },
+    "source_type": {
+      "anyOf": [
+        {
+          "type": "string"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null
+    },
+    "timestamp": {
+      "type": "string"
+    },
+    "unit": {
+      "anyOf": [
+        {
+          "type": "string"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null
+    },
+    "value": {
+      "type": "number"
+    }
+  },
+  "required": [
+    "id",
+    "timestamp",
+    "metric",
+    "value",
+    "created_at"
+  ],
+  "type": "object"
+}

removedOutput schema / properties / result

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

changedOutput schema / required

Previous value: -[
-  "result"
-]New value: +[
+  "measurement"
+]

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

Changed14 schema fields changedv1.0.15Sep 15, 2026

addedInput schema / properties / date
```
Added value: +{
+  "type": "string"
+}
```

removedInput schema / properties / metric

Removed value: -{
-  "description": "Name of the metric, e.g. \"resting_heart_rate\", \"steps\".\nFree-form — not limited to daily_metrics' fixed columns.",
-  "type": "string"
-}

addedInput schema / properties / metric_name
```
Added value: +{
+  "type": "string"
+}
```

addedInput schema / properties / notes

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

removedInput schema / properties / source

Removed value: -{
-  "anyOf": [
-    {
-      "type": "string"
-    },
-    {
-      "type": "null"
-    }
-  ],
-  "default": null,
-  "description": "Where this came from, e.g. \"Apple Watch\", \"manual\". Optional."
-}

removedInput schema / properties / source_type

Removed value: -{
-  "anyOf": [
-    {
-      "type": "string"
-    },
-    {
-      "type": "null"
-    }
-  ],
-  "default": null,
-  "description": "Category of source, e.g. \"wearable\", \"manual\", \"app\". Optional."
-}

removedInput schema / properties / timestamp

Removed value: -{
-  "description": "When the observation was taken, YYYY-MM-DD or a full\nISO 8601 timestamp (YYYY-MM-DDTHH:MM:SS).",
-  "type": "string"
-}

removedInput schema / properties / unit / description

Removed value: -"Unit the value is in, e.g. \"bpm\", \"kg\". Optional."

removedInput schema / properties / value / description
```
Removed value: -"The numeric reading."
```

changedInput schema / required

Previous value: -[
-  "timestamp",
-  "metric",
-  "value"
-]New value: +[
+  "date",
+  "metric_name",
+  "value"
+]

removedOutput schema / properties / measurement

Removed value: -{
-  "properties": {
-    "created_at": {
-      "type": "string"
-    },
-    "id": {
-      "type": "integer"
-    },
-    "metric": {
-      "type": "string"
-    },
-    "source": {
-      "anyOf": [
-        {
-          "type": "string"
-        },
-        {
-          "type": "null"
-        }
-      ],
-      "default": null
-    },
-    "source_type": {
-      "anyOf": [
-        {
-          "type": "string"
-        },
-        {
-          "type": "null"
-        }
-      ],
-      "default": null
-    },
-    "timestamp": {
-      "type": "string"
-    },
-    "unit": {
-      "anyOf": [
-        {
-          "type": "string"
-        },
-        {
-          "type": "null"
-        }
-      ],
-      "default": null
-    },
-    "value": {
-      "type": "number"
-    }
-  },
-  "required": [
-    "id",
-    "timestamp",
-    "metric",
-    "value",
-    "created_at"
-  ],
-  "type": "object"
-}

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

changedOutput schema / required

Previous value: -[
-  "measurement"
-]New value: +[
+  "result"
+]

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

Addedv1.0.11Sep 13, 2026

TDQS

A4.7/5.0

Behavior4/5

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

Annotations only supply basic flags (readOnly=false, destructive=false, idempotent=false), so the description adds value by disclosing that data becomes part of the conversation sent to the client's model and noting the local SQLite context. It could add more about duplicate handling or write confirmation, but the output schema and basic annotation profile cover the rest.

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 front-loaded with the core definition, followed by tight bulleted usage rules and a relevant privacy note. Every sentence earns its place; there is no filler or repetition of schema details.

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 6-parameter tool with a full input schema and an output schema, the description covers granularity, sibling routing, and a meaningful privacy behavior. Nothing essential is missing for an agent to select and invoke the tool correctly.

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

Parameters4/5

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

Schema coverage is 100%, so the baseline is 3, but the description adds semantic meaning beyond the schema: it frames the event as a raw point-in-time observation versus a daily summary, explains that source/exact-time/multiple-same-day-readings are the deciding factors, and gives a concrete example that maps metric, source, and timestamp to a real use case.

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 states the specific verb 'record' with a clear object ('a single raw observation') and defines the exact scope as one metric, one value, one point in time. It explicitly contrasts itself with log_daily_metric and log_workout_session, so an agent can distinguish it from siblings 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 provides explicit 'Use this tool when' and 'Do not use this tool when' sections, naming the exact alternative tools (log_daily_metric, log_workout_session) and the conditions that route to each. It even includes a concrete example, leaving little to inference.

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

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