register_app

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

With no annotations, the description carries the behavioral burden and handles it well: it reveals that creds are fake, that MockPost treats them as real-service creds, and that identity is derived from them. This gives the agent a genuine mental model of registration and idempotent update semantics.

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, each earning its place: action plus credential types, MockPost identity behavior, and the update rule. The credential list is front-loaded and the update guidance is a natural final sentence.

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 tool with no output schema and no annotations, the description is largely complete: it defines what to pass, how identity works, and how to update. Minor gaps are lack of explicit mention of the optional creds/default and any return or error behavior, but these do not block correct invocation.

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?

Input schema coverage is 0%, so the description must supply parameter meaning. It explains 'name' as the binding key and lists representative values for 'creds' (bot token, Twilio SID, Stripe sk_test_, etc.). It doesn't spell out that creds is optional or defaults to null, but the parameter role is clear.

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?

Opens with 'Register or update an app', a specific verb and ressource, and immediately explains the binding of FAKE credentials to a name. It lists concrete creds types (Telegram, Twilio, Stripe, WhatsApp, FCM) which distinguishes it from vaguer sibling tools. 'Use the same name to update creds' clarifies the dual create/update nature.

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 explains that this tool is used when you need to bind fake service creds to a name, and explicitly tells callers to reuse the same name to update existing creds. It does not name alternative tools such as set_app or delete_app, but the intended usage is clear enough without needing exclusions.

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