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

With no annotations, the description carries the full burden and does disclose key behaviors: leases expire unless refreshed, refresh requires lease+token, the token is shown only once, and exclusive/once modes refuse conflicting holders. It omits failure/error behavior and what the call returns, but the lifecycle semantics are unusually well covered.

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 definition is short and front-loads the core action, but the metaphorical phrasing ('when the light allows', 'be alone') trades clarity for style and the mode semantics are compressed into fragments. It is compact without being reliably parseable.

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 an 8-parameter mutation tool with no annotations and no output schema, the description covers modes, expiry and refresh well but leaves hops and intent unexplained and says nothing about return values or conflict/error responses. Adequate for the core path, incomplete at the edges.

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 100%, so the baseline is 3, but the description adds real meaning: it explains the refresh contract for lease/token, the liveness meaning of ttl, and the semantics distinguishing mode values. It does not address hops or intent beyond the schema, so it is above baseline but not exhaustive.

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 concrete verb+resource (take a lease on a key) and enumerates the three modes with distinct semantics. However, the framing phrase 'when the light allows' is opaque and the definition never names siblings like release or look, so the resource is clear but the tool's place in the set is only partly inferable.

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?

It gives usable mode-selection guidance (shared=be counted, exclusive=refused while another holds it, once=exactly once ever) and describes the refresh path. But there is no explicit routing against siblings (release, mark, look) and no stated when-not conditions, so usage is implied rather than directed.

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