Usage and spend

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

With no annotations, the description carries the full burden and does well: it discloses 'reads only', the org-admin API key prerequisite, and that the buckets are written unchanged to a file in the output directory (and printed when small). It stops short of stating rate limits, failure modes, or file naming.

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?

It is a single, heavily parenthesized run-on sentence that packs a lot in but is hard to parse; the most important facts (what it returns, the file output) are buried mid-sentence. Information density is high, but front-loading and readability suffer.

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?

There is no output schema, and the description compensates by describing the returned buckets, the per-product/unit/currency aggregation, and the file artifact. For a 4-parameter read tool with an org-admin auth requirement, this covers most of what an agent needs to call it correctly.

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 100%, so all four parameters (sources, start_time, end_time, bucket_width) are already documented in the schema. The description restates the default window and the summing dimensions but adds no format or syntax detail beyond the schema, so the baseline of 3 applies.

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 a specific resource (billed API/org usage) and what it returns (time buckets of line items summed by product, unit, currency), which separates it from ideogram_invoices, ideogram_quote and ideogram_generation. It never names a sibling explicitly, so the discrimination is inferential rather than stated.

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?

It gives useful context -- default range of the last 7 days by day, and the need for an API key owned by an org admin -- but never says when to prefer this over ideogram_invoices or ideogram_generation, nor any exclusion. Usage is implied by the resource rather than spelled out.

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