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

Annotations declare non-read-only (readOnlyHint=false) and non-destructive (destructiveHint=false), which is appropriate for a write operation that modifies the schedule. The description adds that it 'logs an answer row' and affects the review schedule, but does not disclose side effects like overwriting or requiring authentication. It does not contradict 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?

The description is two sentences, front-loaded with the core purpose and effect, and adds the critical edge case about missing flashcards. No wasted words.

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 5-parameter tool with no output schema, the description is reasonably complete: it explains the purpose, the effect on the schedule, and the edge case behavior. However, it lacks explicit guidance on parameter interactions (e.g., how 'source' and 'context' are used) and does not describe the return value or success criteria, but it is adequate for most use cases.

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 only 20%, but the description clarifies the 'confidence' parameter: it determines the boost weight, and mentions the 'lang' parameter's behavior (scoped on base). However, it does not add semantic detail for 'word', 'source', or 'context'. The description adds some value beyond the schema but not enough to fully compensate for the low coverage.

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's purpose with a specific verb ('mark') and resource ('word demonstrated'), and specifies the effect ('Confidence-weighted spaced-repetition boost...'). It distinguishes from the sibling tool 'mark_struggled' by indicating it is for correct usage.

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?

Provides explicit when-to-use: when the user has used a word correctly InternetHigh, and implies the opposite for 'mark_struggled'. Also notes that it logs an answer row even if no flashcard exists, which is a key contextual detail.

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