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

With no annotations, the description must fully disclose behavior. It adds that the code has limited validity and a daily limit, which are important constraints. However, it does not explain what happens on invalid email or whether the action is idempotent. The agent instructions are more procedural than behavioral.

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 relatively concise at two sentences. It front-loads the core action ('KROK 1 rezervácie: pošle 6-miestny overovací kód...'). The inclusion of step-by-step agent instructions adds some verbosity but is still acceptable given the tool's role in a multi-step process.

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?

The tool is simple (one param, no output schema) and the description covers the core action and constraints. However, it lacks details on the return value or success confirmation, which is notable given the absence of an output schema. The sibling tool 'verify_code' suggests a flow, but the agent might need more on what to expect after calling this tool.

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 baseline is 3. The description does not add new semantic details about the 'email' parameter beyond what the schema already states ('E-mail zákazníka'). It merely contextualizes the email as the customer's for verification.

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 sends a 6-digit verification code to the customer's email, using a specific verb ('posle') and resource ('overovací kód'). It explicitly identifies this as step 1 of a reservation, distinguishing it from sibling tools like 'verify_code' which handle the subsequent verification step.

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 contextual usage guidance by labeling this as 'KROK 1 rezervácie', implying it should be used first in a reservation flow. However, it does not explicitly state when to use this tool versus alternatives like 'verify_code', nor does it specify conditions to avoid use (e.g., existing verified customer).

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