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

Annotations already declare readOnly, idempotent and non-destructive, and the description adds substantial behavior on top: each call is metered as one execution, sessionId must come from execution_session_open, results return inline in roughly two seconds or fall back to async polling via operation_status/operation_output, and the call must not be resent. This is exactly the extra context annotations cannot carry.

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 when-to-use condition, then stacks the operational constraints (auth source, metering, latency, async fallback, no-resend) in a dense but readable way. Every clause carries information; the only minor weakness is that the run-on final sentence packs several distinct rules together.

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 carries the return-behavior burden and does so: it explains the inline short-result case, the ~2s threshold, and what to do with returned IDs when the result is not inline. Combined with 100% schema coverage, an agent has everything needed to call and follow up 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 every parameter (including deadlineAt, idempotencyKey and efficiencyProfile) is already documented in the schema. The description restates that sessionId comes from execution_session_open and that operationId must be new, but adds no syntax or format detail beyond the schema. Baseline 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 resource and outcome: the stable identity (repository root and remote) of a project folder. It also positions itself in the pipeline relative to project_target_resolve and project_target_register, so an agent can distinguish it from the other project_* siblings without opening a 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?

Gives explicit triggering context ('when you need the stable identity of a project folder') and an ordering rule ('before project_target_resolve or project_target_register'). It does not state any exclusion or negative case for when to skip it, but the usage context is clear and actionable.

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