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

No annotations are supplied, so the description carries the full burden of behavioral disclosure, yet it says nothing about the effect of a successful confirmation, whether the code is single-use, how expired or invalid codes are reported, or whether authentication is required. For a tool that mutates verification state, this is a substantial gap.

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 a single short sentence with no filler, and the action is front-loaded. Its brevity is efficient rather than padded, though the compactness reflects under-specification rather than deliberate economy.

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, with one required parameter and full schema coverage, so little is needed. However, with no annotations and no output schema, the description should still explain what the agent gains from a successful call and how it differs from verify_email, and it does neither.

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% and the single required parameter is already documented as 'Code from the email'. The description only adds that it is the code 'the client received', which is a marginal clarification over the schema, so a 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 gives a specific verb and resource, 'Confirm the email code', so the agent knows the action targets a code rather than an address or account. However, it never explains how it differs from the sibling verify_email, so the purpose is clear in isolation but not distinguishable from a near-duplicate tool.

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?

There is no when-to-use guidance at all: no indication of when to call confirm_email versus verify_email or confirm_phone, no stated preconditions such as the code having been requested first, and no mention of expiry or retry behavior. The agent must infer the selection rule from the tool name alone.

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