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

Annotations already flag it as a non-readOnly, open-world, non-idempotent write, and the description layers on rich context the annotations don't carry: the reply is publicly visible, irreversible ('cannot be taken back'), requires a user-confirmation step before sending, and needs inbox access. The retry caveat about unconfirmed sends is genuinely useful behavioral guidance.

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?

Front-loaded with the action and its public/irreversible nature, then practical workflow rules, then the precondition. Every sentence carries distinct operational value with no filler.

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?

There is no output schema, and the description compensates by describing the observable outcome behavior ('if the answer says Instagram did not confirm...'), the visibility/reversibility profile, and the access requirement. An agent has everything it needs to call this correctly and handle the response.

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 100%, so both parameters (text length limit, comment_id source) are already documented in the schema. The description reinforces the comment_id source but adds no syntax or format detail beyond what the schema provides, so the baseline of 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?

States a specific verb and resource ('Post one public reply under an Instagram comment') plus the account scope ('from the account that got the comment'). This clearly separates it from sprkly_reply_to_dm, which handles private messages rather than public comment replies, without needing to open either schema.

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 concrete when-to-use guidance: take comment_id from sprkly_get_inbox_thread, show the words to the user first, and a specific failure rule (if Instagram did not confirm, don't resend). It also states the prerequisite ('Needs inbox access'). It stops short of explicitly naming the alternative sibling (sprkly_reply_to_dm) and the condition that would select it instead.

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