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

Annotations already declare readOnlyHint and openWorldHint, and the description adds genuinely useful context beyond them: the upstream is ESPN's public site JSON, times are UTC, and — most importantly for an agent — the tool is paid ($0.002 USDC per successful call via x402) with failed calls not charged. It stops short of describing caching or rate-limit behavior, so not a 5.

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 purpose and payload are front-loaded in the first clause, followed by defaults and then the pricing caveat — a sensible order. The pricing sentence is long but contains decision-relevant information (cost, payment rails, failed-call policy), so little is wasted.

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 an output schema present, return values need not be explained, and both optional parameters are fully specified in the schema. The description covers source, defaults, timezone, and billing, leaving only minor gaps like pagination or behavior for invalid league codes.

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 both parameters are already documented including the YYYY-MM-DD format and the eng.1 default. The description restates the same defaults (English Premier League, UTC) without adding format examples or league-code guidance beyond what the schema provides, so the baseline 3 applies.

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 and resource ('ESPN soccer scoreboard for one league and date') and enumerates the returned fields (home/away team, score, status, stadium), so an agent can distinguish it from siblings like dev_espn_standings or dev_espn_sports without opening the schema.

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 gives the default parameters (eng.1 league, yesterday UTC) and the data source, which implies when the tool is applicable, but never says when to prefer it over alternatives such as dev_fbref, dev_flashscore, or dev_understat_xg that also cover soccer. No exclusions or prerequisites are stated.

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