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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds a small amount of behavioral context by indicating the output is one line at a time and intended for voice/TTS, but it says nothing about ordering, whether cards repeat across dates, or how n relates to a reading.

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 text opens with a duplicated title (including a stray double period) and then spends most of its length on a generic catalog listing (Theogony, Iliad, Odyssey, Poetic Edda) that is irrelevant to invoking this specific tool. It is both padded and poorly front-loaded for a decision the agent must make quickly.

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?

There is no output schema, so the description carries the burden of explaining the return value, and it does not: an agent cannot tell whether a card is a verse line, a plan step, or a summary, nor how many cards a reading contains. For a read tool with three parameters and no required fields, that gap is significant.

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%, and each of the three optional parameters (n, date, reading) has a clear inline description with defaults, so the schema does the heavy lifting. The tool description contributes no additional parameter meaning, which is the baseline 3 case.

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 first sentence simply restates the title ("Today's reading one line at a time, for voice.."), and the second is a server-wide catalog blurb about Greek and Norse myth content rather than a statement of what get_card returns. It never defines what a "card" is, nor distinguishes this tool from the sibling get_reading or get_today, so an agent cannot tell which one to pick from the text alone.

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?

There is no explicit when-to-use guidance. The phrases "daily readings" and "search" gesture at the surrounding feature set but never say when to call get_card instead of get_reading, get_today, or read_book, even though all four are close siblings.

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