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

Annotations already declare it is a non-destructive, non-idempotent write (readOnlyHint=false, idempotentHint=false, destructiveHint=false). The description adds real context beyond them: the auth/account requirement and, importantly, what is returned (the starter with its id and a link where photos are added) — valuable because there is no output schema.

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 compact sentences, front-loaded with the action and resource, and the prerequisite/return details are appended rather than buried. The return clause is slightly convoluted ("a link, where photos are added") but nothing is wasted.

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 simple single-object create tool with full schema coverage and annotations covering the safety profile, the description supplies the missing pieces: the account prerequisite and the shape of the response. Only explicit sibling routing and any failure/validation behavior are absent.

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 name, notes, story and birthday (including the YYYY-MM-DD format and today-default). The description restates the same fields in prose without adding format, constraint or interaction details, so the baseline 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?

The description states a specific verb ("Add") and resource ("sourdough starter") scoped to the baker's Loafy account, and enumerates the payload fields. It is clearly a creation tool, distinct from update_starter and list_my_starters by verb and noun, though it never explicitly names or routes to those siblings.

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?

Usage is only implied: an agent can infer this is for creating a brand-new starter rather than modifying an existing one, but no when-to-use/when-not-to-use guidance or explicit alternative (e.g. update_starter) is given. The prerequisite note ("Needs the baker's Loafy account") is helpful but is a condition, not routing guidance.

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