List Heartbeats

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

With no annotations, the description carries the full burden of disclosing behaviors. It reveals default behavior: 'By default returns only the most recent heartbeat per monitor.' It also discloses a security-relevant behavior: credentials in status message URLs are masked as '***' unless includeSecrets is set, and warns that the output is persisted in logs, adding important context about data exposure. This goes beyond the baseline and provides meaningful transparency.

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?

The description is structured logically, leading with the main purpose, then usage guidance, then parameter details, and finally a security note. It is somewhat dense but not verbose; each sentence adds value. The repetition of maxHeartbeats in different contexts is justified for clarity. Overall, it is concise while covering necessary information.

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?

Given the output schema exists (though not shown), the description need not explain return values. It covers the tool's scope, default behavior, parameter semantics, and a potential side effect (log persistence). It does not mention error conditions or authorization, but for a list endpoint with a clear schema, the provided information is sufficient to understand and use the tool effectively.

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 schema covers all parameters with descriptions, but the tool description adds crucial semantic detail. For count and limit, it explains they are aliases and recommends maxHeartbeats. For maxHeartbeats, it specifies the default (1) and the maximum (100). For includeSecrets, it clarifies the default (off), the effect on output, and the global configuration option. This enriches the schema and leaves no ambiguity about parameter usage.

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 clearly states the tool's primary function: 'Retrieves historical heartbeat data for ALL monitors.' It specifies the resource (heartbeat data) and the scope (all monitors), distinguishing it from sibling tools like getHeartbeats which likely target a single monitor. The mention of 'response times, status changes over time' further clarifies what the data contains.

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 provides explicit usage context: 'Use this for analyzing patterns across multiple monitors or correlating events.' It also explains when to adjust parameters: 'By default returns only the most recent heartbeat per monitor; set maxHeartbeats for historical analysis.' While it does not explicitly mention alternative tools, the emphasis on 'ALL monitors' implies that for single-monitor queries, a different tool might be appropriate, giving adequate guidance.

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