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

With no annotations, the description carries the full burden and does so largely: it discloses the return shape (category breakdown, time series, currency split, top 5 payees, biggest day, summary with limit utilization, per-line spent plus otherSpent fallback) and the daily/weekly/monthly granularity cutoffs (62/184 days). The implied read-only nature and decimal amount format are covered, though permissions/auth expectations are not mentioned.

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-loaded with the core purpose followed by tightly packed detail, and every sentence adds information about returns or granularity. It is dense to the point of being a single long run-on paragraph, which slightly hurts scannability.

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 returns, and it does so comprehensively: breakdowns, time series, currency, payees, summary metrics, per-line attribution and the otherSpent bucket. An agent has everything needed to call it and interpret the result.

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% for the single trackerId parameter, so the schema already documents it; the description adds no extra semantics about the ID format or source. Baseline 3 applies when the schema does the heavy lifting.

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?

States a specific verb and resource ('Get spending statistics for a tracker') and immediately scopes the output (category breakdown, expense-vs-income time series over the tracker period). It also references the sibling get_trackers as the source for lineId matching, so an agent can tell what this tool is for without opening a schema.

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 is implied (analyzing a tracker's spending), but the description never states when to prefer this over siblings like get_spending_by_categories, get_cash_flow, or get_trackers. It does explain the internal granularity thresholds, which is useful but not a when-to-use rule.

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