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

Beyond the annotations, the description discloses two real behavioral traits: it notifies no one ('reaches no one, so it runs without asking first') and it requires an API key with access to this app. This meaningfully supplements the readOnlyHint=false/openWorldHint=true annotations, which would otherwise leave the notification/blast-radius question open.

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?

The opening 'Knowify: Add a client to your client list. Adds a client to your client list and returns...' is redundant, and the dangling 'It reaches no one' pronoun requires interpretation. The useful information (return value, auth) is present but not tightly front-loaded.

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 mutation tool with no output schema, the description helpfully states the return value (client_id) and the auth requirement, which is the key missing context. It is nearly complete; only explicit creation-vs-lookup guidance is absent.

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 the schema already documents all four parameters. The description only restates the email semantics ('used for proposals and invoices'), which the schema field description already contains, so it adds no meaning beyond the structured data.

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?

The description states a specific verb and resource ('Add a client to your client list') and ties the output to a sibling action ('returns its client_id for create_job'), letting an agent distinguish it from read-only siblings like knowify_list_clients. It is clear, though the first two sentences are near-duplicates rather than adding distinct scope detail.

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?

Usage is only implied: the mention that the returned client_id feeds create_job suggests this tool runs before job creation, but there is no explicit when-to-use or when-not-to-use guidance relative to knowify_list_clients or other client tools.

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