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 the owner_key auth requirement, that the call is free, that the figure is an audit-log estimate rather than a guarantee, and that young workspaces skew the hourly rate. It doesn't restate the read-only nature of the call or mention rate limits.

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?

Front-loads the deliverable and is dense with useful detail, including the output field names (measured_since, covered_seconds, shortened) that no output schema provides. The young-workspace caveat is stated twice in slightly different words, which is the one element that doesn't fully earn its place.

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, so the description must describe return values — and it does, enumerating the windows, the runway figures, the top spending sub-keys, and the per-window measurement metadata. Nothing an agent needs to interpret the response is missing.

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 coverage is 100% — both api_key (including the sub-key 403 behavior) and workspace_id are fully documented in the schema. The description's 'Owner_key required' reinforces the auth rule but adds no syntax or format detail beyond it, so the baseline 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?

Names a specific resource and deliverable — burn rate and runway, spend per hour over 1h/24h/7d windows, top spending sub-keys — so an agent knows exactly what it computes. It never explicitly contrasts itself with the adjacent sibling aanet_get_remaining_balance, so the boundary between 'balance' and 'forecast' is left to inference.

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?

Gives clear operational context: 'Owner_key required; free' and a concrete use case — pair with a balance_low webhook to be warned before a 402. It stops short of naming an alternative tool to use instead when only a raw balance is wanted, and states no exclusions.

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