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

Annotations already declare non-read-only, idempotent, non-destructive, closed-world behavior. The description adds value beyond that by disclosing the response payload (Pioneer/Member badge markdown) and a security trait: third-party text arrives under "untrusted_content" with a "_notice" and must be treated as data, not instructions. That prompt-injection warning is genuinely useful context annotations cannot convey.

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 tight sentences: action first, then the required-parameter constraint, then return value, then the untrusted-content caveat. No filler, and the ordering puts the actionable constraint before the edge-case warning.

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?

With no output schema, the description correctly covers the return value (badge markdown) and the untrusted-content wrapper. For a mutation tool with idempotentHint=true, most behavioral risk is already covered by annotations. Residual gap: `showName` semantics and whether signing is permanent are not addressed.

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 75%, near the high-coverage baseline, and the schema already documents `token` and `firstWord` in detail. The description adds sourcing semantics for `acceptCharter` (must match the version from `carta`), but says nothing about `showName`, which has no schema description at all.

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 and resource ("Sign the Charter") and adds what happens as a result (badge markdown in the response). It also ties itself to the sibling `carta` tool as the source of the accepted version, which helps separate it from related tools like `carta_reserve` or `join`. It stops short of fully framing the outcome (membership? registration?) in one line.

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 prerequisite is clear: acceptCharter must be the exact version obtained from the `carta` tool, which implies reading carta first. However, there is no explicit when-to-use versus when-not guidance relative to siblings such as `join`, `carta_reserve`, or `first_word`, and no note on whether signing is repeatable or one-time.

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