list_decks

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds real behavioral context beyond that: cards generated from an Obsidian vault cannot be created through this server, mixed decks partially accept add_notes, and counts include subdecks except own_cards. It doesn't address ordering or scale, but for a read-only listing that is minor.

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?

Front-loaded one-line summary of the resource and return shape, followed by compact, labeled source definitions and a separator explanation. Every sentence carries information; nothing is restated from the annotations or name.

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, parameterless read tool with an output schema present, the description covers everything an agent needs: what is listed, what each source value implies for writes, and how deck names decompose. Field-level return formatting is legitimately left to the output schema.

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?

There are zero input parameters, so the baseline is 4. The description instead invests in defining the semantics of returned fields (source values, 'own_cards' vs subdeck-inclusive counts) and the '::' subdeck separator with a worked example, which is genuinely useful for interpreting output.

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+resource ('List all Anki decks') and immediately enumerates what comes back (new/learning/due/own cards plus source), which no sibling provides. The source taxonomy further distinguishes it from search_notes/get_notes/add_notes by making clear this is a deck-inventory tool, not a content tool.

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?

Gives concrete routing guidance tied to each source value: read/quiz freely for yanki, 'add_notes works' for anki and mixed, and 'prefer Obsidian for technical topics.' It tells the agent when writes will and won't work. It stops short of explicitly saying when to call list_decks instead of get_weak_cards or search_notes, so it's context rather than a full when/when-not rule set.

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