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

Annotations already cover read-only, idempotent, non-destructive, closed-world behavior, so the description's value-add is the calculation method: the 5/9-of-1%-per-month reduction for the first 36 early months, 5/12 after that, 2/3-of-1% delayed credits, and SSA dime rounding. This lets an agent sanity-check returned values. One gap: the 'born after 1942' qualifier hints at an unstated branch for earlier birth years, leaving that edge case opaque.

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?

It is a single front-loaded sentence that names the output first, then the method, with no filler. The statutory percentages are dense but each earns its place as verification context; the one weak spot is that the sentence is long enough that the 'born after 1942' clause is easy to miss.

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 correctly identifies the return value as a monthly dollar benefit and notes dime rounding. It is missing only the output type/shape and the treatment of the pre-1943 birth case, minor omissions for a four-parameter pure calculation 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 description coverage is 100%, so all four parameters are already documented, and the baseline is 3. The description adds only modest meaning beyond the schema — clarifying that pia is the full-retirement-age monthly amount and that claim ages run 62 to 70 — and says nothing about claim_age_months or how birth_date drives the FRA used in the math.

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 states a precise computation — the monthly retirement benefit at a given claiming age between 62 and 70, derived from the PIA — with both input and output semantics clear. An agent can distinguish it from calculate_cola_increase, calculate_earnings_test, and get_full_retirement_age without opening any schema, since those cover cost-of-living, work-limit, and FRA lookup tasks respectively.

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 62-to-70 age range and the requirement that the starting point be the full-retirement-age amount imply when the tool applies, but there is no explicit statement of when to use this vs. the sibling calculators or what prerequisites must be satisfied (e.g., that the FRA itself comes from get_full_retirement_age). Usage is inferable rather than stated.

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