Learnings

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

Annotations already flag destructiveHint=true and readOnlyHint=false, so the safety baseline is set; the description adds real value on top by disclosing that reaffirm stamps the review date and that other projects' text is untrusted (an injection warning). It does not explain what makes an update destructive or whether changes are reversible, which is the one gap against a destructiveHint=true tool.

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 compact sentences with read operations front-loaded, then mutations, then the capture alternative, then the untrusted-content caveat. The telegraphic style ("Read lessons: list, search (query), show (learningId)") packs a lot in, though the parenthetical-heavy syntax takes a beat to parse.

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 15-parameter, five-action tool with no output schema, the description covers action routing, the sibling alternative, and the security caveat, and the schema carries the rest at 93% coverage. Remaining gaps are pagination behavior and whether updates return the modified record, both minor against the structured data available.

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 93%, so nearly every parameter is already documented in the schema, and the description largely restates those mappings (query for search, learningId to read or change). It adds no syntax, format, or constraint detail beyond what the schema provides, which is the expected baseline here.

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 enumerates concrete verb+resource pairs for each action: list, search (query), show (learningId), update status/evergreen, and reaffirm, which stamps the review date. It also explicitly names the sibling rbook_session for capture, so an agent can tell which tool owns which operation without opening a schema.

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?

Each action value is paired with its intended use and the parameter it needs (query for search, learningId for show/update/reaffirm), and the capture case is explicitly redirected to rbook_session(action="capture", category="learning"). What's missing is guidance on choosing between update and reaffirm, or between list and search, when both could apply.

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