get_player_achievements

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the agent knows this is a safe read operation. The description adds meaningful context beyond these: it requires a public profile and game ownership, and it requires an API key. This is valuable behavioral context that annotations don't capture. It could go to 5 if it mentioned rate limits or specific failure modes for non-public/non-owned profiles, but what's here adds value without contradicting annotations.

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?

Three sentences with zero waste. The primary purpose is front-loaded, the return format is summarized next, and the prerequisites are last. Every sentence earns its place without redundancy.

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 that an output schema exists (the tool has has_output_schema: true), the description needn't detail return values in depth, and its summary of the return shape (completion + list with dates) complements the output schema. The tool is moderately complex (profile ownership, public visibility, API key) and the description covers these prerequisites. Slight gap: it could mention what happens if the profile is private or doesn't own the game, but for the typical agent flow this description 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 both parameters well, including examples for both appid and steam_id. The description adds value by mentioning the return shape (overall completion and list of unlocked achievements), which helps the agent understand what the parameters do together. It doesn't explain format details of steam_id beyond schema examples, but schema coverage is high enough that the description doesn't need to repeat it. Being slightly above baseline 3 because it clarifies the purpose of the combination.

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 clearly identifies the tool as showing a player's achievement progress in one game, specifying the resource (achievements), the action (show progress), and the scope (one game). It distinguishes itself from siblings like get_global_achievement_percentages (which is global, not per-player) and get_game_schema (which lists achievements but not player progress).

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 explicitly states when to use this tool: to see a player's achievement progress for a specific game. It also implicitly excludes when not to use it (e.g., for global percentages, use get_global_achievement_percentages; for schema, use get_game_schema). The prerequisites for use (profile must be public, must own the game) are clearly stated, helping the agent decide when this tool is applicable.

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