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

Annotations already declare readOnlyHint=true, matching the description's read-only nature. The description adds value by explaining the output scope (single player, 2026 season) and that it's free. However, it doesn't mention rate limits, data freshness, or whether missing players return errors or empty results. With good annotations, a 3 is appropriate for minor additional context.

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 a single, dense paragraph that front-loads the core purpose and output, then provides use-case examples. It's well-structured but slightly verbose in listing all output items; could be tighter with bullet points or fewer examples. Still, every sentence earns its place.

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 3 parameters (all documented in schema), no output schema, and moderate complexity (enums for scoring/platform), the description covers the key behavioral aspects (what's returned, free access, query types). It doesn't describe pagination or error handling, but for a simple single-player lookup, this is adequate.

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 the schema already documents all 3 parameters (player, scoring, platform). The description adds value by mentioning the scoring options (standard, half-PPR, full-PPR) and noting that platform applies default settings overridable by explicit scoring. This enriches the schema defaults but doesn't add entirely new meaning, so baseline 3 fits.

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 starts with a specific verb ('A single player's 2026 fantasy outlook') and lists exactly what the output contains (projected points, floor/ceiling, ADP, rank, tags). It clearly distinguishes from siblings by focusing on a single player's outlook, unlike tools like compare_players or sleepers_and_busts which handle multiple players or broader analysis.

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?

Includes explicit query examples like 'is <player> a sleeper', '<player> fantasy outlook 2026', 'should I draft <player>', and '<player> projection', making it obvious when to use. Also states 'Free, no key' to set expectations about no authentication. The sibling context (e.g., sleepers_and_busts, compare_players) implies alternatives, though not explicitly named, but the examples are sufficient.

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