explain_recent_cost_drivers

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

No annotations are provided, so the description carries full burden. It discloses the comparative window behavior, free tier operation, and that it finds top drivers of increase and decrease. It does not mention authorization, rate limits, or return format, but covers the core read-only analysis adequately.

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 well-structured with a clear first sentence, behavioral explanation, usage examples, and parameter list. It is concise (under 200 words) and front-loaded with the primary purpose.

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 adequately covers the tool's purpose and behavior for a read-only analysis tool. It lacks explicit output format details (no output schema given), but the mention of 'summarizes net change' and 'top drivers' gives a reasonable expectation.

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 description explicitly documents both parameters ('days' as comparison window length with default 30, 'top_n' as number of top drivers with default 10), adding meaning beyond the input schema's type and defaults.

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 verb 'explain' and resource 'cost changes across all connected providers in the last N days'. It distinguishes from siblings like 'get_top_cost_drivers' by specifying the comparative analysis (same-length prior period) and free tier availability.

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 lists explicit use cases ('Why did my bill go up?', etc.) and mentions it works on the free tier without business metrics. It does not directly contrast with sibling tools, but the use cases cover common scenarios.

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