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

With no annotations, the description carries the burden well: it discloses that any key may read it, that it reveals no activity, that the signature is Ed25519 by the service, and that the call is free. It omits rate limits and error/edge behavior, but adds substantial behavioral context beyond 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 core purpose and the returned fields, then appends the verification rationale and public-key URL. Dense but every sentence carries information; the parenthetical asides are slightly heavy but not wasteful.

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 tool with no output schema and no annotations, the description covers the return fields, access model, cost, cryptographic algorithm, the public-key retrieval URL, and the intended verification procedure. An agent has everything needed to call and use it correctly.

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 description coverage is 100%, so api_key and workspace_id are already fully documented in the schema. The description adds no additional parameter meaning, so the baseline of 3 is appropriate.

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 ('Signed tip of the workspace's tamper-evident activity chain') and immediately enumerates the exact return shape {seq, entry_hash, signed_at, key_id, algorithm, signature}. It is clearly distinguishable from siblings like aanet_get_activity, aanet_get_activity_summary, and aanet_export_activity.

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 a concrete when-to-use scenario ('Save it OUTSIDE AANet... if the operator later rewrote or deleted earlier rows, a fresh export no longer contains your saved entry_hash at that seq'), which frames the verification workflow. It does not explicitly contrast with or exclude the sibling activity/export tools, so it stops short of naming alternatives.

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