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

Annotations only declare readOnlyHint=false and destructiveHint=false; the description goes beyond that by disclosing that a null lease is returned when another agent holds an active lease, and by stating the write-access prerequisite. It stops short of explaining expiry/renewal semantics beyond what the schema's duration_ms already says.

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 tight sentences with the core action and constraint front-loaded, no filler. Dense enough to be a little packed, but every clause carries information.

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 a 6-parameter coordination tool with no output schema and minimal annotations, the description covers the write prerequisite, the return semantics (null on contention), and addressing modes. Missing only a pointer to the release counterpart and lease-expiry expectations, which are minor relative to what's covered.

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 83%, so the schema already documents target_id, duration_ms, target_type, owner, and repo. The description usefully synthesizes the two target-addressing patterns, but mostly restates format information the schema provides, so it sits at the baseline.

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?

Names a specific verb (acquire) and resource (exclusive lease) scoped to PRs, issues, branches, or file paths, and states the precondition 'in a repository you can write.' It's clearly distinct from the sibling gluecron_release_lease, though it never names that counterpart 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?

Explains the two addressing modes (owner+repo with a bare key, or target_id '<repository id>:<key>') and ties the tool to 'one of your agent sessions.' It gives clear invocation context but does not say when to prefer this over, or pair it with, the release counterpart, nor when to avoid leasing.

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