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

Annotations already cover read-only/idempotent/non-destructive safety, but the description adds substantial behavioral detail: long-run drift is re-anchored to stated assumptions, costs are ON by default, the model preserves path shape from the substrate while overriding drift, and the tool is explicitly non-advisory. It also discloses the block-bootstrap chaining method and that both the raw stress drift and re-anchored drift are echoed in output — valuable context beyond annotations.

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?

The description is dense but well-structured: it opens with the core purpose, proceeds to methodological details (block chaining, drift re-anchoring), then outputs, and ends with a caveat. Every sentence conveys necessary information for a complex tool, with no filler or redundancy. It is appropriately sized given the tool's sophistication.

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?

Given the tool's complexity (10 parameters) and the presence of an output schema, the description covers all critical context: input modes (savings/withdrawal), methodology (chained blocks, drift re-anchoring), default behaviors (costs on, inflation indexing), output types, and usage limits (descriptive, not advisory). It leaves no major gaps for an agent to misuse the tool.

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%, so baseline is 3. The description adds value by clarifying how monthly_contribution and monthly_withdrawal define mutually exclusive plan modes, notes that monthly_withdrawal is inflation-indexed by default (reinforcing schema), and explains that long_run_drift overrides the re-anchored drift. It also mentions costs being ON, which relates to implicit parameters not in the schema, enriching parameter understanding.

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?

The description clearly specifies the tool's function: it computes distributions of multi-year wealth paths for savings or withdrawal plans, and explicitly lists the outputs (quantiles, ruin probabilities, sequence-of-returns diagnosis, drift-sensitivity). It distinguishes itself from generic stress tests by focusing on long-horizon savings/withdrawal scenarios, making the purpose unambiguous.

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 description implies when to use the tool: for evaluating multi-year savings or withdrawal plans, particularly with inflation-indexed withdrawals and re-anchored drift. It does not explicitly name alternative tools like portfolio_stress_test, but the context ('savings plan', 'withdrawal plan') provides clear situational guidance. No exclusions are stated, but the intent is clear.

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