analyze_nrr

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

With no annotations, the description provides behavioral context: it returns 'building' status until enough MRR snapshots exist, and highlights the divergence between logo and revenue retention. This adds value beyond basic functionality.

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 relatively concise, front-loading the main purpose and key metrics. The narrative about divergence is informative but slightly verbose; still, it earns its place by explaining the tool's unique value.

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 a single optional parameter and no output schema, the description covers the tool's purpose, output components (NRR, logo retention, churn split, accounts), and a caveat about the 'building' status. It is adequately complete for this straightforward tool.

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 single parameter window_days has 100% schema coverage, but the description adds meaning by specifying its default (90) and the condition for when it matters (enough daily MRR snapshots). This helps the agent decide appropriate values.

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 that the tool analyzes Net Revenue Retention, explaining both revenue-weighted and count-weighted metrics, expansion/contraction/churn split, and top accounts losing MRR. This specific verb-resource combination distinguishes it from siblings like analyze_funnel or analyze_nps.

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 explains that NRR is a key investor metric that no standalone tool can compute, implying appropriate use cases. It mentions the optional window_days parameter and the 'building' status, but lacks explicit guidance on when not to use this tool or alternatives.

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