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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered, and the description adds genuinely new behavior: source links in results, explicit truncation, availableSections/missingSections coverage reporting, and error semantics (isError with suggestions, never an automatic substitute). What it omits is any note on cost, rate limits, or how large a full non-brief payload can get.

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?

Four tight sentences with the core purpose front-loaded and no filler. Some phrasing is telegraphic ("truncation is explicit") and depends on the reader already knowing the response envelope, which costs a little readability.

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?

Because an output schema exists, the description needn't document return values, and it correctly spends its budget on error behavior and coverage reporting instead. The remaining gap is the missing routing guidance against the two sibling tools, which matters for a lookup tool in a three-tool family.

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?

With only 50% schema coverage, the description compensates where it matters: the undocumented `card` parameter is explained as accepting names, slugs, numeric names, and Coins aliases, which the schema says nothing about. `brief` and `sections` are re-described at roughly the level the schema already gives, and `orientation` is only alluded to ("orientation meanings by default") rather than explained.

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 states a specific verb and resource ("Read authored meanings" for a tarot card) and the title reinforces the lookup intent. It does not, however, explicitly distinguish itself from siblings search_tarot_cards and get_tarot_spreads, so the agent must infer that this is the identifier-based detail fetch.

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 gives parameter-level usage advice ("Use brief for bounded plain-text excerpts", "sections selects exact normalized section IDs") but never says when to call this versus search_tarot_cards or get_tarot_spreads. Usage is implied by the accepted identifier formats rather than stated as a routing rule.

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