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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description is free to add genuinely new context: that output includes `chart_hints` rendering directives and that the `senaro-charts` MCP server renders them locally over stdio only. That cross-server dependency and the calculation-not-advice caveat are real additions beyond the structured fields.

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?

Four tight sentences: disclaimer first, then what the analysis produces, then the return-side chart_hints note and its server dependency. No filler, and the most safety-relevant sentence is front-loaded.

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 return-value burden and does so — it enumerates the analysis outputs and the chart_hints field. The only gap is any guidance on input prerequisites or how this compares to calculate_cc_payoff, which would complete the picture.

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% and the nested toolArguments object documents every field, including the notable distinction that minimum_payment binds here but not in calculate_cc_payoff. The description adds nothing beyond the schema, 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?

States a specific verb and resource: 'Deep analysis of a single card's cash advance' with named outputs (payment allocation, CA interest cost, CA payoff months, growth). The 'single card' / 'CA' scoping does implicitly distinguish it from broader debt tools like calculate_cc_payoff, though it never names a sibling directly in the description.

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 only guidance is 'Calculation, not advice. Verify with a professional before acting,' which is a liability disclaimer rather than a when-to-use condition. It gives no criteria for choosing this tool over calculate_cc_payoff or compare_strategies, even though the schema itself flags a behavioral divergence from calculate_cc_payoff.

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