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

Beyond the annotations (readOnlyHint=false, destructiveHint=false), the description discloses partial-update semantics and two hard preconditions - ownership and non-archived state - that would otherwise cause surprising failures. It doesn't state whether the operation is reversible or what happens to tags on failure that the schema already covers (tags overwrite).

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 short sentences, all front-loaded: the action first, then the partial-update contract, then the precondition. No filler and nothing repeated from the schema.

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 needn't explain return values, and annotations already carry the safety profile. The ownership constraint, patch semantics, and archived precondition cover what an agent needs to invoke this mutation 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 params are already well documented, including the enum tradeoffs for acceptedPaymentMethods. The description names a subset of fields (title, description, tags) but adds no semantics beyond what the schema already says, so baseline 3 applies.

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 uses a specific verb and resource ("Update the metadata of an existing need you own") and lists concrete updatable fields (title, description, tags). It distinguishes itself implicitly from create_need and archive_need through the word "metadata" and the ownership scope, though no sibling is named explicitly.

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 description gives a clear precondition ("The need must not be archived") and ownership requirement, plus the PATCH-style contract that only provided fields change. What's missing is an explicit pointer to alternatives such as archive_need for state transitions or create_need for new records.

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