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

Annotations already cover the safety profile (readOnly/idempotent/non-destructive), so the bar is lower, and the description still adds real behavior: the search is exact unless the node limit is hit, plus the return contract (DK ids in slot order) and the scoring model per mode. It stops short of noting runtime or plan limits, but this is well beyond what the annotations give.

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 lineup format, then mode behavior, then supported knobs, then the solver caveat and return format. Dense but every clause carries information; minor redundancy in restating the CPT 1.5x and both-teams constraint.

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 15 optional params and no output schema, the description compensates well: it explains the return value, the optimization modes, and the solver's exact-vs-node-limit behavior. It doesn't restate the slate_id prerequisite from mlb_list_slates, but that lives in the schema.

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 3 is the baseline, but the description goes further by explaining the semantics the schema only labels: gpp scores ceiling minus an ownership penalty, cash scores projection, own_lambda 0 removes ownership, and it ties the listed knobs (captain, locks, excludes, per-team cap, reliever switch, hitter cap) together meaningfully.

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 (Builds) and resource (DraftKings MLB Showdown lineups) and pins down the exact format: 1 CPT at 1.5x plus 5 FLEX under $50,000 with both teams required. This distinguishes it cleanly from the sibling invoke_mlb_optimizer (classic format) and invoke_mlb_showdown.

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 explains what gpp vs cash does and how key knobs behave (own_lambda 0 removes ownership), which is implied guidance for mode selection. However, it never states when to reach for this tool versus invoke_mlb_optimizer or the other showdown siblings, and offers no explicit exclusions.

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