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

Annotations already declare readOnlyHint/idempotentHint, so safety is covered; the description goes further and discloses the full return payload, including the on_track/at_risk/over_budget vocabulary, the is_bill tagging, and the 14-day event horizon. For a tool with no output schema, this is precisely the behavioral context an agent needs.

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 purpose, then the return contents, then usage conditions and alternatives — a logical agent-friendly ordering. The dense enumeration of return fields is informative rather than padded; every sentence carries selection-relevant information.

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?

With no output schema, the description carries the full burden of explaining return values and does so exhaustively, plus clarifies scope (point-in-time, 14-day forward window) and sibling boundaries. An agent can decide and call correctly from this alone.

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?

Only one optional parameter, and the schema already documents its fallback behavior at 100% coverage. The description adds nothing parameter-specific, which is acceptable given the schema does the work, but it doesn't reinforce the auto-resolution of user_id.

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+resource ('Point-in-time financial health check') and enumerates exactly what comes back (net worth, cash position, spending pace with projection, budget traffic lights, action items, upcoming events). It is clearly distinguishable from siblings like month_end_review and spending_comparison, which it names.

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 explicit when-to-use ('quick daily or weekly check-in', 'how am I doing financially RIGHT NOW') and explicitly routes three alternatives to their own conditions: month_end_review for retrospective, spending_comparison for two periods, list_events for events only. Nothing is left to inference.

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