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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds real value by disclosing the data sources behind the projection (history-derived recurring patterns, outstanding invoices, tax deadlines), which tells the agent what the numbers are built from. No mention of latency or data-freshness caveats.

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 identity (13-week cash-flow forecast) before the content enumeration and then the usage triggers. The return-value list is long but each item earns its place since there is no output schema. Slightly dense.

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 obligation to explain return contents and does so item by item; annotations cover behavior and the lone parameter is fully documented in schema. An agent has everything needed to call and interpret it.

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?

Single optional `company` parameter with 100% schema description coverage — the schema fully explains defaulting and how to discover companies via list_companies. The description adds nothing about the parameter, which is acceptable at this coverage level but not above baseline.

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 resource (13-week cash-flow forecast) and enumerates exactly what it returns: bank balance, weekly inflows/outflows/running balance, low point, recurring patterns, outstanding invoices, tax deadlines. This clearly separates it from near siblings like get_balance or get_financial_snapshot.

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 concrete user-intent triggers: cashflow, runway, "can I afford X", "when will I run out", planning ahead. Strong positive routing signal, though it names no explicit alternative tool or exclusion (e.g. vs get_balance for a point-in-time figure).

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