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

With no annotations, the description carries the full burden and delivers: cost ('Free'), the exact EIP-191 signed message format, replay protection rationale (hash binding prevents reuse with a different key), and the 5-minute server-clock validity window. This is rich behavioral context an agent could not infer from the schema.

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?

Front-loads the action after a one-word cost cue, and every sentence carries required information. The parenthetical explaining the hash-then-sign ordering is necessary but makes the text dense; three long clauses in one sentence could be marginally clearer.

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 5-required-param mutation with no annotations and no output schema, the description covers the signing contract, timing, and dependency chain well. It stops short of describing the success response or the exact error behavior on a rejected signature, which leaves a small gap.

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 only 20%, yet the description gives meaning to essentially every one of the 5 parameters: id's origin (after store_persistent_memory), timestamp's unit and validity (Unix epoch ms integer, within 5 minutes), wrappedKey's role in the SHA-256 hash, readerPubKey's role as the reader's key, and signature's algorithm and signed payload.

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 ('registers a wrapped content key for a specific reader's public key') and immediately names the cryptographic proof mechanism that distinguishes it from siblings like share_memory_key. An agent can tell what this tool does and how it differs from sibling key/memory tools.

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?

Gives clear preconditions and timing constraints: '{id} only exists after store_persistent_memory returns' and 'sign at call time; a pre-signed or archived signature will be rejected.' It does not explicitly state when to prefer this over share_memory_key, so it stops short of full when/when-not guidance.

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