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

Annotations already declare destructiveHint=true, idempotentHint=false and openWorldHint=true, so the safety profile is covered. The description adds the useful partial-update contract and the personal-vs-project scoping rule, but says nothing about side effects of a destructive update (e.g. assignee replacement, completion cascades) that would justify the destructive flag.

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?

Three short sentences, zero filler, with the core action and the partial-update guarantee front-loaded before the scoping detail. Appropriately sized for a tool whose parameters are fully documented in the schema.

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?

An output schema exists, so return values need no explanation, and the 100%-covered parameter schema handles field-level detail. The description supplies the two things the schema can't: partial-update semantics and the personal-vs-project targeting rule. Minor gap on side effects of the destructive semantics.

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 100% across 8 parameters, so the schema already documents due-date formats, assignee replacement, Markdown descriptions and the projectId fallback. The description duplicates the projectId guidance rather than adding new semantics; baseline 3 is appropriate.

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?

Specific verb + resource ("Update an existing task"), clearly distinguished from sibling mutators like xtiles_create_tasks and xtiles_delete_tasks by the 'update' verb. It does not explicitly name or contrast a sibling, but the purpose is unambiguous.

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 explicit conditional guidance on the key routing decision: supply projectId for project tasks, omit it for personal tasks. It also clarifies the partial-update mode ('Only specified fields will be updated'), so the agent knows this is a patch, not a replace. No alternatives or exclusions beyond that.

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