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

Annotations already declare the mutation and open-world profile (readOnly=false, idempotent=false). The description adds genuinely useful context beyond them: it only applies to failed entries and it appends a new record to the log rather than overwriting the old one, which matters for a non-idempotent retry.

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?

Two short sentences, front-loaded with the action and its scope, then the side effect. No filler; every clause carries information an agent needs.

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 two-parameter mutation tool with no output schema, the description covers the action, the eligibility condition, and the resulting side effect. It lacks detail on failure handling (e.g., what happens if the original send failed for a permanent reason) but is otherwise sufficient to call correctly.

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 are already documented, and the schema even states that log_id comes from get_quiz_email_log. The description adds no format, constraint, or meaning beyond what the schema provides, so the baseline 3 is appropriate.

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?

Specific verb+resource: resends an email from the mailing log, restricted to entries with status = failed. This is clearly distinct from get_quiz_email_log (which only reads) and from send_quiz_email_test. It stops short of explicitly naming a sibling, but the scope is unambiguous.

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 parenthetical '(status = failed)' implies the precondition for use, and the schema points to get_quiz_email_log as the source of the ID. However, there is no explicit when-to-use/when-not guidance, no mention of how to obtain a valid log_id in the description itself, and no routing to alternatives.

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