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

Annotations already declare readOnly=true, idempotent=true, destructive=false, so the safety burden is covered. The description adds behavior beyond them: 'Required skills are included', disclosing that reads are transitive and a single call may return more than one skill — a non-obvious dependency detail. It does not describe output size or format.

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 opening sentence is front-loaded with the instruction and the three highest-stakes examples; the bulleted list is a routing table where each line earns its place. It is long, but the length is driven by 26 required enum values, not by filler, so only the mild duplication of the schema enum counts against it.

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?

With one required enum parameter fully documented and no output schema, the description supplies everything needed to select and invoke it, including the ordering rule. Minor gap: it never says what a skill's contents or size look like, though that is secondary for a read-only lookup.

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 coverage is 100% and the enum already constrains skillId. The description goes beyond the bare enum by attaching a usage scenario to each of the 26 values, so an agent can pick the right ID from semantics rather than guessing. Baseline is 3; the per-value meaning raises it to 4.

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 ('Read the matching Cactal skill') and frames the timing ('before acting'), which is enough to separate it from the sibling docs_read/docs_search tools and from the action tools it gates. The enumerated skill IDs make the scope concrete rather than abstract.

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?

Provides an explicit decision table: source-editing-workflow before source edits, design-direction for design, copywriting for words, plus a per-skill trigger line for all 26 skills. It lacks only an explicit 'when not to use / skip reading' exclusion, which keeps it at 4 rather than 5.

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