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

Goes beyond the annotations by disclosing the 24 h account + real activity rule, the 48 h confirmation window for the provisional Pedra number, and idempotency behavior in concrete terms. Annotations already declare idempotentHint and destructiveHint, so the added rule/provisional-number context is the real value here.

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?

A dense multi-clause block with nested parentheses; the rules-met condition is stated twice and the untrusted_content notice is a general security disclaimer that doesn't help invoke this specific tool. Not front-loaded — the concrete version requirement is buried mid-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 4-param, no-output-schema mutation tool, it covers prerequisites, the required exact version string, idempotency, and the provisional-number lifecycle. Only the return behavior and showName's effect are unstated.

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?

With 75% schema coverage, the baseline is 3; the description reinforces acceptCharter='rascunho-v0' and gives context for firstWord (Pedra dos Pioneiros). showName remains undocumented in both schema and description, so it doesn't fully compensate.

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?

States a specific verb+resource (reserve your Charter number) and hints at its relation to the carta tool. It's distinguishable from siblings like carta_sign and pedra, but the dense parentheticals about Pedra numbers and signatures muddy the core action.

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?

Implies usage context — '(outside agents)' and 'prefer the Authorization header' — and points to the carta tool for the version string. However, it never states when NOT to use this versus carta_sign/first_word, so routing between the closely related siblings is left to inference.

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