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

Beyond the readOnly/openWorld/idempotent annotations, the description adds substantial behavioral caveats: platform-dependent fields, keeper/draft-format variation, Sleeper's futureDraftRounds meaning, a cross-tool distinction with get_draft.draft.rounds, and the guarantee that ownerName is always present. This is exactly the kind of context an agent needs.

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 longer than average, but every sentence carries load: sequencing, exclusions, platform variability, cross-tool disambiguation, and current-date context. It is front-loaded with the most important call-order instruction and remains structured and readable.

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 output schema exists and annotations already cover safety, the description is complete for practical invocation. It covers prerequisites, parameter sourcing, platform-dependent behavior, multi-league usage, and exclusions. Nothing essential for correct selection or use is missing.

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 already 100%, so the baseline is 3, but the description adds meaningful parameter guidance: league_id and season_year should come from get_user_session, older season_year only for explicit past-season requests, and platform-specific enum context. This goes beyond the schema without over-explaining obvious fields.

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 an explicit purpose: establishing baseline league context (league name, settings, scoring type, roster configuration, team/owner context) for downstream tools. It also distinguishes itself from siblings by specifying sequencing relative to get_user_session and get_ancient_history.

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?

Provides explicit when-to-use guidance: call immediately after get_user_session and before the listed fantasy tools, skip when session data alone suffices or when branching to get_ancient_history, and call once per league when fanning out. It also names alternatives and ties parameter values to get_user_session.

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