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

Annotations already indicate readOnlyHint=false, destructiveHint=false, and idempotentHint=true. The description adds that only scheduled posts can be edited, which is a key behavioral constraint. It also implies the tool modifies existing posts (not creating new ones). No contradiction with annotations; the description adds context beyond the annotations.

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 description is two sentences, front-loaded with the main action, and includes a critical constraint. Every word earns its place; no fluff or repetition.

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?

Given the tool's complexity (6 parameters, mutation, no output schema), the description covers the essential behavioral constraint (only scheduled posts) and the main editable fields. It doesn't explain return values, but since there's no output schema, that's not required. The description is sufficient for an agent to understand when and how to use it, though it could mention that all fields are optional replacements.

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 documents all parameters. The description adds value by clarifying that media_ids 'Replaces the whole set, it does not append — pass every slide you want the post to keep.' This is crucial semantic information beyond the schema's basic description. Also, the description mentions 'target accounts' which maps to profile_ids, and 'attached media' to media_id/media_ids, providing a high-level summary.

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 clearly states the tool's purpose: 'Change the caption, publish time, target accounts or attached media on a post that has not published yet.' It specifies the resource (scheduled post) and the actions (change caption, time, accounts, media), distinguishing it from siblings like sprkly_schedule_post (creating) and sprkly_delete_scheduled_post (deleting).

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 provides a clear condition for use: 'Only posts with status "scheduled" can be edited.' This implies when to use the tool (for scheduled posts) and implicitly when not to (for published or draft posts). It doesn't explicitly name alternatives, but the sibling list includes related tools like sprkly_schedule_post and sprkly_draft_post, which are distinct enough.

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