Get SIM Credentials

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

Annotations already declare readOnly/idempotent/non-destructive, so the bar is lower, and the description still adds real value: the server-flag gate and the warning that anyone holding the activation code can install the line. It stops short of describing what happens when the flag is off (error vs. empty) or whether PIN/PUK can be absent for some line types.

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?

Three sentences, zero filler, and the return value is front-loaded before the precondition and the warning. Each sentence carries a distinct fact (what it returns, what it needs, how to handle the output).

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 an annotated read tool with no output schema, this is complete: the returned payload is enumerated in the description (LPA string, QR content, PIN/PUK), the server prerequisite is stated, and the security caveat is given. Nothing an agent needs in order to call it safely is missing.

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% and both parameters are documented in-schema (numberId as 'Line id.', reason as audit-log rationale). The phrase 'for one line' reinforces the idempotent single-target nature of numberId but adds no new syntax or semantics. 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 names the exact resources returned (eSIM activation code / LPA string / QR content and PIN/PUK) and scopes them to 'one line'. No sibling in the list returns SIM secrets, so the agent can route to this tool unambiguously without opening the schema.

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?

It states a hard precondition (TELGEA_ENABLE_SIM_SECRETS=true on the server) and a handling rule ('Give it only to the line's holder'), which is exactly the context an agent needs before calling. It does not name an alternative or a when-not-to-call condition, which keeps it short of a 5.

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