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

The description discloses what the tool returns ('first card's front', 'how many cards are due', 'grading_mode') and instructs the agent on subsequent behavior ('follow its instruction exactly for the whole session'). It also reveals what internal fields are not to be read aloud, showing transparency about output handling.

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 moderately concise and logically structured, with each sentence serving a distinct purpose (what it does, when to use, what it returns, how to behave). It contains some redundancy but remains focused and readable, warranting a score above average.

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 complexity (starting a session, returning graded content, and setting a behavioral contract), the description covers all essential aspects: trigger conditions, output contents, and post-call instructions. No critical context is missing for an agent to use the tool correctly.

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?

The schema already provides 100% coverage with descriptions for both parameters ('tag' and 'deck'). The tool description adds no additional parameter meaning, so the baseline score of 3 applies per the rubric.

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 that the tool starts a study session and explicitly lists the trigger conditions ('whenever the user asks to study, review, practice, quiz, test, or drill their cards'). It also clarifies the intended behavior ('Do not quiz from memory: only sessions record progress'), leaving no ambiguity about the tool's purpose.

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?

It provides explicit when-to-use guidance by naming the exact user intents that should trigger this tool, including edge cases ('even cards created moments ago'). It also differentiates from alternative behavior ('Do not quiz from memory') and explains why this tool is required for progress tracking.

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