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 real value by stating the permission requirement (viewers may add comments) and constraining parentId to an existing root thread, but says nothing about notification side effects, editing/immutability, or rate limits.

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?

A single well-formed sentence with the primary action first and the threading variant second. No filler, no restating of the title.

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 no output schema and four parameters, the definition covers the action, the reply variant, and permissions. It omits what the tool returns (the created comment object or id) and any depth/threading limits, which an agent would want before composing the call.

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 only 25% (workspaceId alone), so the description has to carry weight. It usefully explains parentId's semantics as a reply into an existing root thread, but content (1-5000 chars) and candidateId are left to the schema with no additional meaning, leaving half the parameters under-explained.

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 and resource (add a comment to a candidate) and disambiguates the two modes of operation: top-level comment vs. threaded reply via parentId. It does not explicitly name the sibling tools that overlap (list_candidate_comments, add_role_note), so it stops just short of a 5.

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?

'Viewers may add comments' gives a permission cue for who can invoke it, and the parentId clause implies the when for threaded replies. However, there is no guidance on when to prefer add_role_note or when a reply should be top-level instead, and no exclusions are offered.

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