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

Annotations already declare readOnlyHint=false, idempotentHint=true, destructiveHint=true, and openWorldHint=false, so the safety profile is covered. The description adds a real behavioral fact the annotations lack — the required project_comments:write scope — and the 'existing' qualifier implies the record must already exist, but it never explains what is destroyed, whether content is replaced or merged, or what happens to parent_id if omitted.

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 tightly written sentences with the core operation front-loaded and the authorization requirement trailing. Nothing is redundant and nothing inflates the payload.

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 is not obliged to describe returns, and the annotations carry the safety profile. For a mutation tool, though, it leaves a meaningful gap: partial-update versus full-replacement semantics and how parent_id behaves are never addressed, which an agent needs to call it correctly.

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 the schema already defines id, content, and parent_id with format and constraints. The description only restates that the update is addressed 'by ID' and adds no meaning about optional-field semantics or whether omitted fields are left unchanged.

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 (Update) and resource (an existing project comment) plus the lookup key (by ID), which cleanly separates it from create_project_comment and delete_project_comment. It does not explicitly contrast with sibling update tools (update_work_order_comment, update_asset_comment), but the resource name alone 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?

The description offers no when-to-use guidance, no prerequisites beyond the scope string, and no mention of alternatives such as create_project_comment for new comments or delete_project_comment. An agent gets the operation but not the selection context.

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