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

Annotations already indicate destructiveHint=false, meaning the tool is not destructive. The description adds that it 'never overwrites an existing deck', which provides explicit behavioral context beyond annotations. It also mentions the Pro feature, which is useful. However, it doesn't disclose potential side effects like how it interacts with the user's account or if it requires specific permissions, but the 'never overwrites' is a valuable addition.

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 concise, using three sentences with no filler. The key behavior ('as a NEW deck', 'never overwrites') is front-loaded, followed by a necessary format example that directly aids correct invocation. The 'Deckodex Pro' note is relevant and earns its place. It is well-structured and efficient.

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 tool's relative simplicity with only two parameters and no output schema, the description is fairly complete. It covers the purpose, the new-deck behavior, and the decklist format. However, it lacks details on possible errors (e.g., invalid card codes) or whether the tool creates a new entry in 'my_decks'. The absence of siblings' differentiation is a minor gap, but overall adequate for the complexity.

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?

With a schema description coverage of 0%, the description must compensate for undocumented parameters. It does provide a concrete format example for 'decklist' ('4 GD05-019') and specifies 'one card per line', which adds semantics. However, it doesn't explain the 'name' parameter beyond its schema (max 80 chars), and it doesn't clarify how the decklist string is parsed or if errors return. This is partial compensation but not complete.

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 states the tool saves a decklist as a new deck in the user's Deckodex account, with a specific verb 'save' and resource 'deck'. It distinguishes from 'update_collection' and 'my_decks' by emphasizing 'new' and 'never overwrites', though it doesn't explicitly name a sibling alternative unlike the high-calibration example. The purpose is specific and actionable.

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 clearly states the action—saving a NEW deck and never overwriting—which implicitly sets the context for use (creating a new deck). However, it doesn't explicitly state when NOT to use this tool or how it differs from sibling tools like 'validate_deck' or 'add_to_list'. The line about 'Deckodex Pro' hints at a prerequisite but lacks explicit guidance.

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