compare_periods

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

With no annotations provided, the description carries the full transparency burden. It clearly discloses the computation logic (last N days vs preceding N days), what it returns (current, prior, delta, % change), and the report_type scoping. It does not mention potential side effects, but as a read-only comparison tool this is sufficient.

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, front-loaded with the core purpose. The second sentence adds essential output details and parameter scope. Every word earns its place with no redundancy.

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 description provides enough context for an agent to understand the tool's behavior and outputs. The output schema likely defines the return structure, so the description doesn't need to elaborate further. However, it lacks any exclusions or edge-case warnings, which are minor for a read-only comparison 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?

Schema description coverage is 0%, so the description must compensate. It explains the semantics of 'days' (lookback window) and 'report_type' (scope of totals), while 'account_id' is self-explanatory. This is adequate for the three parameters, though account_id is not explicitly defined.

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 exactly what the tool does: compares the last N days against the preceding N days, with a clear verb ('Compare') and resource ('periods'). It also distinguishes itself from sibling tools like performance_report by specifying the period-over-period comparison.

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 context is implied: an agent would use this when needing a period-over-period comparison, but there is no explicit 'when-to-use' or 'when-not-to-use' guidance, nor any mention of alternatives such as performance_report for single-period data.

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