kv_set

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

Annotations already declare this is a non-read-only, destructive write (overwrites), so the safety picture is partially covered. The description usefully adds cross-session visibility and TTL semantics, but does not clarify overwrite behavior, the meaning of 'small', or any key/value limits despite destructiveHint.

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?

Two short sentences, front-loaded with the core action and followed by the optional modifier. No filler.

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?

Output schema exists and annotations cover the destructive/overwrite profile, so the description need not explain returns. Still, for a cross-session shared-value write tool it omits overwrite semantics and 'small' size expectations, leaving notable gaps.

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 50%; project_id is well documented in the schema while key and ttl_seconds are not. The description adds the unit for ttl_seconds ('in seconds'), a real gain, but says nothing about key naming rules or project scoping beyond what the schema provides.

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?

Specific verb+resource ('Set a small shared JSON value') with scope info ('other sessions can discover'), clearly distinct from kv_get/kv_delete by name and semantics. No explicit sibling differentiation, but the resource is unambiguous.

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 phrase 'other sessions can discover' hints at the cross-session sharing use case, but there is no explicit when-to-use, when-not, or reference to alternative tools. The agent must infer usage entirely from the name and sibling list.

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