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

Annotations already indicate non-read-only, openWorldHint=true, and idempotentHint=true. The description adds the important constraint about idempotency: retrying with the same key and arguments returns the first result glom, and reusing a key with different arguments is refused. This extends beyond the schema fields and clarifies the behavior.

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 extremely concise, only two sentences, with the core function and constraints front-loaded. It avoids unnecessary repetition of schema details and gets to the point quickly.

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 moderate complexity (5 params, all described in schema) and the presence of an output schema, the description is complete. It covers the key usage rule (at least one field), explains the idempotency behavior beyond the schema, and the schema covers the rest.

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?

The schema covers all parameters with descriptions (100% coverage). The description adds no parameter-specific details beyond what the schema already has. However, it does emphasize the requirement for at least one of text or scheduled_at, which is a usage rule not captured in the schema's 'required' array (since none are required). This is a slight value-add, but the schema already explains the parameters well.

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 action ('Update'), the resource ('existing scheduled LinkedIn post'), and the scope (text and/or scheduled time). It is clearly distinguished from siblings like delete_scheduled_post and list_scheduled_posts, which are obvious alternatives.

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 explicitly states the requirement that at least one of text or scheduled_at must be provided, and explains that post_urn should come from list_scheduled_posts. This gives clear guidance on when to use this tool and what inputs are needed.

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