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

Annotations already declare readOnlyHint=false, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds the partial-update trait (send only changed fields), but says nothing about permission needs, reversibility, or whether renaming breaks existing references.

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?

Two short sentences, mutation targets front-loaded, with the operational hint ('send only what changes') in the closing clause. No wasted words.

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 4-param mutation tool with no output schema and annotations covering the safety profile, the description is nearly sufficient. The remaining gap is behavioral consequences of changes (e.g., whether altering sections discards existing content), which an agent might want to know before calling.

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 75% and both color and sections carry schema descriptions, so baseline is 3. The description maps plain-language verbs to parameters ('rename' -> name, 'color', 'sections it shows in') but adds no format or constraint detail beyond what the schema already supplies.

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 on a specific resource and enumerates the three mutable fields (name, color, sections). The resource 'sphere' clearly separates it from the update_task/update_goal/update_subgoal siblings, though it does not explicitly name a sibling to avoid.

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?

'Send only what changes' gives genuine patch-semantics guidance for a mutation call, which is more than nothing. However, it offers no when-to-use context against alternatives (add_sphere for creation, archive_sphere for removal) and no prerequisites.

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