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

Annotations already declare readOnlyHint=false, idempotentHint=true, and destructiveHint=false, so the mutation and repeat-safety profile is covered. The description adds a genuine domain consequence — starring enrolls the word in a separate practice deck — but says nothing about permissions, failure modes, or what happens to existing deck membership when unstarring.

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?

Two compact sentences with the action and the consequence front-loaded; every clause earns its place and nothing is padded.

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?

For a simple idempotent two-parameter toggle with a full output schema, the description is essentially sufficient — action, UI analogue, and outcome are all present. Only the lack of edge-case behavior (unstarring effect on the practice deck) keeps it from complete.

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%, including 'true to star the word, false to unstar it' on the boolean, so the schema fully carries parameter meaning. The description's 'stars or unstars' merely mirrors that mapping without adding format or constraint detail.

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 pair (stars/unstars) on a specific resource (a word), and clarifies the semantics with the UI analogue 'as the star on its card does.' This clearly separates it from neighbors like update_word or set_retired, though it does not name those siblings directly.

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 phrase 'Starred words have their own practice deck' implies why an agent would star something, but there is no explicit when-to-use guidance, no exclusion against update_word or set_retired, and no stated prerequisites (e.g., does the word need to exist?).

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