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

Annotations only declare readOnly=false, idempotentHint=false, destructiveHint=false; the description goes well beyond them by disclosing the per-project advisory lock, cycle detection for inverse edges, and the same-project constraint. It does not say what happens on a detected cycle (error vs. silent) or whether duplicate edges are rejected despite the non-idempotent hint.

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 sentences, front-loaded with what the tool does, then constraint, then behavioral detail — no filler and nothing repeated from the schema.

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 3-parameter mutation with no output schema, the description covers project scoping, directionality, and concurrency behavior adequately. It stops short of describing failure modes (cycle detected, duplicate edge, unknown story key) that an agent would need to interpret results.

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 67% and the two story parameters already carry descriptions; the description's real contribution is explaining the semantics of each enum value (directed with cycle check vs. symmetric/unrestricted), which the schema does not. Because the schema does most of the work, a 3 baseline with credit for the enum meaning 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 verb and resource ('Create a directed relation between two stories') and enumerates the three relation types, so an agent knows exactly what the tool produces. It does not differentiate itself from the nearby create_cross_link or list_story_relations siblings, which keeps it from a 5.

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 useful selection context by explaining that BLOCKS/DEPENDS_ON are directed and cycle-checked while RELATED_TO is symmetric and unrestricted, which helps pick a relation type. However, it never says when to use this tool rather than create_cross_link, nor does it mention preconditions such as needing the stories to exist first.

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