Retrieve second-by-second heart rate data for a watch-paired training session, including average, max, min, and a downsampled series. Returns unavailable when no watch recorded it.
Second-by-second heart rate for a watch-paired session: average, max, min and a series (downsampled to at most 600 points). available:false when no watch recorded it.
| Name | Required | Description | Default |
|---|---|---|---|
| training_id | Yes |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full load, and it does disclose meaningful behavior: the return granularity (second-by-second), the downsampling cap (at most 600 points), and the degraded-run case (available:false when no watch recorded). It omits auth/rate-limit considerations, but for a read-only getter those are minor.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two tight sentences with the core content front-loaded; the payload list and the edge case are packed in without filler. Slightly comma-dense but every clause earns its place.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a single-parameter read tool with no annotations and no output schema, the description covers the return shape and the empty case well, which is the main gap left by the absent output schema. It is incomplete on the input parameter and on when to prefer this over session-level siblings.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
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, yet it never names or explains training_id. The phrase 'for a watch-paired session' only loosely implies a session identifier and adds no format, validity, or lookup detail beyond the self-explanatory parameter name.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
States a specific verb and resource: it retrieves second-by-second heart rate for a watch-paired session, and enumerates the exact payload (average, max, min, series). This is far more than a restated name. It does not explicitly differentiate from nearby siblings like get_session_detail or get_training_stats, which keeps it out of the top band.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Usage is only implied: the phrase 'for a watch-paired session' and 'available:false when no watch recorded it' signal the precondition under which the tool is meaningful. There is no explicit when-to-use versus alternatives nor any routing to a sibling. Minimum-viable implied guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.