fc create comment

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

Annotations already declare destructiveHint=true, idempotentHint=false and openWorldHint=true, but the description adds non-obvious behavior: it renders Markdown, links attached media, mutates the parent feed's comment count, may trigger hooks/announcements/automations affecting other people, and must not be retried. That is exactly the extra context annotations cannot carry.

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?

The first sentence front-loads purpose and side effects and the confirmation/no-retry warnings come last, which is the right order. The 'Controller:' and 'Route source:' lines are largely noise for an agent making a tool-selection decision.

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 non-idempotent, destructive create tool with no output schema, the description covers confirmation requirements, blast radius via hooks/automations, and retry behavior. Return-value shape is unspecified, but that is a minor gap given the annotations and high schema coverage.

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 coverage is high (83%) and the schema itself explains account, confirm, feed_id, payload and payload_file semantics, so the description need not repeat them. However, 'threaded reply' implies parent/thread targeting that has no corresponding parameter, adding slight ambiguity rather than clarity; baseline 3.

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 ('Posts a comment or a threaded reply on a feed item') and enumerates the concrete side effects (Markdown rendering, media linking, comment-count bump). This clearly separates it from fc_update_comment, fc_delete_comment and fc_list_comments without opening their schemas.

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 gives a real precondition ('Explicit local confirmation is required') and a caution against retrying, which shapes when and how to call it. It stops short of naming sibling alternatives or stating when-not to use this tool, so it is context-rich but not fully explicit routing.

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