Update viewer heartbeat

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

The annotations show readOnlyHint=false, indicating a write operation; the description's 'Updates' aligns with that. It adds the behavioral purpose of keeping the session alive, but does not disclose side effects, failure modes, or the optionality of viewerSessionId. Given the annotations, this is adequate but not rich.

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 sentences. The first sentence is a tautological restatement of the title ('Update viewer heartbeat'), while the second adds the substantive detail. It is concise, but the redundancy could be trimmed without losing meaning.

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?

The tool is a simple one-parameter mutation with no output schema, so the bar for completeness is moderate. However, the description does not mention that viewerSessionId is optional, how the session ID is obtained (likely from termix_metrics_register_metrics_viewer), or any error behavior. The description is minimally sufficient to grasp the tool's purpose but lacks enough context for correct invocation.

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?

The input schema contains one string parameter, viewerSessionId, with no description (0% coverage). The description does not explain the parameter's meaning or how to obtain it, only referring to a 'metrics viewer session,' which is a weak hint. Since schema coverage is low, the description fails to compensate, leaving the agent without enough semantic detail.

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?

The description states the action explicitly: 'Updates the heartbeat timestamp for a metrics viewer session to keep it alive.' It identifies the verb (updates), the resource (heartbeat timestamp for a metrics viewer session), and the purpose. This clearly distinguishes it from sibling tools like termix_metrics_register_metrics_viewer or termix_metrics_unregister_metrics_viewer, which create or destroy sessions.

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?

The description implies the tool is used to keep a viewer session alive, but it does not explicitly state when to use it versus alternatives (e.g., termix_metrics_register_metrics_viewer). It offers no exclusions or conditions, leaving the agent to infer usage from the 'keep it alive' phrase.

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