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

Goes beyond the annotations (readOnlyHint=false, idempotentHint=true, destructiveHint=false) by disclosing the downstream effect on ranking: a starred skill is ranked first by find_skill when it fits and never shown when it does not. It also defines the reply contract ("Reply with the returned line") for a tool with no output schema. It does not address whether starring persists across sessions or any permission requirements, so a small gap remains.

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?

One dense paragraph with the gating condition front-loaded, followed by effect, parameter source, and reply instruction — no filler sentences. The only minor blemish is listing "unstar it" inside the star/save example set.

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 no output schema, the description supplies the missing return guidance ("Reply with the returned line"), plus the prerequisite lookup, the unstar path, and the ranking consequence. An agent has everything needed to decide to call it and to report the result.

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%, so all three parameters are already documented, and the description largely restates them ("set starred to false to unstar" duplicates the schema's default note). It does add the mildly useful instruction to pass both Source and Skill as printed by find_skill, though it implies source is expected while the schema marks it optional.

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 pair (star/unstar) and resource (a skill for this user), and explicitly disambiguates from siblings by scoping to user-requested starring rather than the automatic ranking behavior of find_skill or the scoring of rate_skill.

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?

Gives an explicit trigger condition ("Only when the user asks to star, favourite or save"), concrete example utterances, and a hard exclusion ("Never call it on your own initiative"). It also routes the agent to find_skill as the prerequisite source of the skill/source values.

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