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

Annotations already declare idempotentHint=true and destructiveHint=false, so safety is covered; the description adds the non-annotation fact that the call 'always returns the list of available projects' and that omitting the param clears state. That return/state behavior is genuine value beyond the structured fields, though it doesn't note what happens for an invalid projectId.

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?

Four short sentences, front-loaded with the prerequisite fact, then the two call modes, then the return guarantee. No sentence is filler and nothing repeats the title.

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 supplies the missing return-value information, and with annotations covering safety and idempotency, an agent has everything needed to call this correctly. It covers prerequisite, invocation, and result.

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% and the single parameter is fully documented in the schema itself. The description's note about omitting projectId to clear and list projects largely restates the schema description rather than adding syntax or error semantics, so the baseline of 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?

States a specific verb pair and resource (set/clear project context) and is unmistakably distinct from every sibling, which all operate on flows, steps, records, or tables. An agent can identify this as the session-scoping tool without opening the schema.

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?

Explicitly states the triggering condition ('All tools require a project context to operate') and both invocation modes: with a projectId to select, without to clear. It doesn't name alternative ways to establish context, but for a prerequisite session tool this is clear, actionable guidance.

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