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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds meaningful behavioral context: the Vilna layout, collapsible Rashi/Tosafot, click-to-translate, and the default behavior of showing the day's daf yomi when no argument is given. This goes beyond the schema and 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 compact, front-loaded with the core function, and every sentence earns its place: the layout, the interactive features, the default behavior, and the usage trigger with examples. No fluff.

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 read-only viewer with 2 optional parameters and no output schema, the description covers the main behavior, defaults, and usage trigger. It doesn't describe the return format, but since there's no output schema and the tool is a visualizer, the agent can infer the result is a rendered page. Minor gap: no mention of error cases (e.g., invalid ref), but this is acceptable for a read-only tool.

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%, so the schema already documents both parameters (ref and langue) with examples and defaults. The description adds the default daf yomi behavior for ref, which is useful, but doesn't add much beyond the schema. Baseline 3 is appropriate.

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 states a specific verb ('Affiche'), a precise resource (page de Guemara en visualiseur interactif façon Vilna), and the key features (texte au centre, Rachi/Tossafot dépliables, traduction au clic). It also gives concrete example invocations ('montre-moi le daf du jour', 'ouvre Berakhot 2a'), which clearly distinguishes it from siblings like sefaria_text or sefaria_search.

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 explicitly says 'Utiliser dès que l'utilisateur veut VOIR ou étudier un daf' and provides example user requests. This gives clear when-to-use guidance. It doesn't explicitly name alternatives, but the sibling list is large and the examples make the trigger condition unambiguous.

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