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

Annotations already declare the safety profile (readOnlyHint=false, destructiveHint=true, idempotentHint=true), so the bar is lower. The description usefully adds the required auth scope, which is not in the structured fields, but it never explains the destructiveHint=true flag or what an update can overwrite — an odd omission for a tool flagged destructive.

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 terse sentences with no filler, and the 'by ID' identifier is front-loaded. It is appropriately sized, though its brevity reflects missing content rather than tight editing.

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 mutation tool with rich annotations, no output schema, and full schema coverage, the definition is minimally adequate. The auth scope is covered, but the destructive semantics and partial-update behavior are not addressed, leaving a gap that annotations alone don't close.

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%, so all eight parameters (including the required id and the timeframe enum) are already documented in the schema. The description adds no parameter-level meaning beyond this, so the baseline 3 applies.

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 states a specific verb and resource ('Update an existing project update by ID'), which is clear and precise. It doesn't differentiate itself from the many sibling update_* tools, but the resource name 'project update' is unambiguous enough that an agent can identify it.

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?

It states the required scope (project_updates:write) but gives no guidance on when to use this versus update_project or create_project_update, nor any conditions or exclusions. The only usage signal is a permission prerequisite, which is thin.

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